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Recent advances of interface engineering in inverted perovskite solar cells Shiqi Yu(余诗琪), Zhuang Xiong(熊壮), Zhenhan Wang(王振涵), Haitao Zhou(周海涛), Fei Ma(马飞), Zihan Qu(瞿子涵), Yang Zhao(赵洋), Xinbo Chu(楚新波), and Jingbi You(游经碧) Chin. Phys. B, 2022, 31 (10): 107307.   DOI: 10.1088/1674-1056/ac8e9f Abstract （359）   HTML （8）    PDF （8178KB）（1498）       Knowledge map    Perovskite solar cells (PSCs) have witnessed great achievement in the past decade. Most of previous researches focus on the n—i—p structure of PSCs with ultra-high efficiency. While the n—i—p devices usually used the unstable charge transport layers, such as the hygroscopic doped spiro-OMeTAD, which affect the long-term stability. The inverted device with the p—i—n structure owns better stability when using stable undoped organic molecular or metal oxide materials. There are significant progresses in inverted PSCs, most of them related to charge transport or interface engineering. In this review, we will mainly summarize the inverted PSCs progresses related to the interface engineering. After that, we prospect the future direction on inverted PSCs.

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Thermoelectric generators and their applications: Progress, challenges, and future prospects Nassima Radouane Chin. Phys. B, 2023, 32 (5): 057307.   DOI: 10.1088/1674-1056/aca5fd Abstract （194）   HTML （2）    PDF （2763KB）（665）       Knowledge map    Our community currently deals with issues such as rising electricity costs, pollution, and global warming. Scientists work to improve energy harvesting-based power generators in order to reduce their impacts. The Seebeck effect has been used to illustrate the capacity of thermoelectric generators (TEGs) to directly convert thermal energy to electrical energy. They are also ecologically beneficial since they do not include chemical products, function quietly because they lack mechanical structures and/or moving components, and may be built using different fabrication technologies such as three-dimentional (3D) printing, silicon technology, and screen printing, etc. TEGs are also position-independent and have a long operational lifetime. TEGs can be integrated into bulk and flexible devices. This review gives further investigation of TEGs, beginning with a full discussion of their operating principle, kinds, materials utilized, figure of merit, and improvement approaches, which include various thermoelectric material arrangements and utilised technologies. This paper also discusses the use of TEGs in a variety of disciplines such as automobile and biomedical.

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Variational quantum simulation of thermal statistical states on a superconducting quantum processer Xue-Yi Guo(郭学仪), Shang-Shu Li(李尚书), Xiao Xiao(效骁), Zhong-Cheng Xiang(相忠诚), Zi-Yong Ge(葛自勇), He-Kang Li(李贺康), Peng-Tao Song(宋鹏涛), Yi Peng(彭益), Zhan Wang(王战), Kai Xu(许凯), Pan Zhang(张潘), Lei Wang(王磊), Dong-Ning Zheng(郑东宁), and Heng Fan(范桁) Chin. Phys. B, 2023, 32 (1): 010307.   DOI: 10.1088/1674-1056/aca7f3 Abstract （626）   HTML （12）    PDF （3465KB）（663）       Knowledge map    Quantum computers promise to solve finite-temperature properties of quantum many-body systems, which is generally challenging for classical computers due to high computational complexities. Here, we report experimental preparations of Gibbs states and excited states of Heisenberg $XX$ and $XXZ$ models by using a 5-qubit programmable superconducting processor. In the experiments, we apply a hybrid quantum-classical algorithm to generate finite temperature states with classical probability models and variational quantum circuits. We reveal that the Hamiltonians can be fully diagonalized with optimized quantum circuits, which enable us to prepare excited states at arbitrary energy density. We demonstrate that the approach has a self-verifying feature and can estimate fundamental thermal observables with a small statistical error. Based on numerical results, we further show that the time complexity of our approach scales polynomially in the number of qubits, revealing its potential in solving large-scale problems.

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Fundamental study towards a better understanding of low pressure radio-frequency plasmas for industrial applications Yong-Xin Liu(刘永新), Quan-Zhi Zhang(张权治), Kai Zhao(赵凯), Yu-Ru Zhang(张钰如), Fei Gao(高飞),Yuan-Hong Song(宋远红), and You-Nian Wang(王友年) Chin. Phys. B, 2022, 31 (8): 085202.   DOI: 10.1088/1674-1056/ac7551 Abstract （476）   HTML （0）    PDF （11486KB）（604）       Knowledge map    Two classic radio-frequency (RF) plasmas, i.e., the capacitively and the inductively coupled plasmas (CCP and ICP), are widely employed in material processing, e.g., etching and thin film deposition, etc. Since RF plasmas are usually operated in particular circumstances, e.g., low pressures (mTorr-Torr), high-frequency electric field (13.56 MHz-200 MHz), reactive feedstock gases, diverse reactor configurations, etc., a variety of physical phenomena, e.g., electron resonance heating, discharge mode transitions, striated structures, standing wave effects, etc., arise. These physical effects could significantly influence plasma-based material processing. Therefore, understanding the fundamental processes of RF plasma is not only of fundamental interest, but also of practical significance for the improvement of the performance of the plasma sources. In this article, we review the major progresses that have been achieved in the fundamental study on the RF plasmas, and the topics include 1) electron heating mechanism, 2) plasma operation mode, 3) pulse modulated plasma, and 4) electromagnetic effects. These topics cover the typical issues in RF plasma field, ranging from fundamental to application.

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Reconstruction and functionalization of aerogels by controlling mesoscopic nucleation to greatly enhance macroscopic performance Chen-Lu Jiao(焦晨璐), Guang-Wei Shao(邵光伟), Yu-Yue Chen(陈宇岳), and Xiang-Yang Liu(刘向阳) Chin. Phys. B, 2023, 32 (3): 038103.   DOI: 10.1088/1674-1056/acb912 Abstract （665）   HTML （24）    PDF （7614KB）（593）       Knowledge map    This work presents a strategy for the mesoscopic engineering of hierarchically structured sodium alginate (SA) aerogels to enhance the macroscopic performance. The strategy was implemented by meso-functionalizing and reorganizing SA aerogels via controlled heterogeneous nucleation, in which microcrystalline cellulose-manganese dioxide (MCC-MnO2) nano-crystallites worked as template. Due to the short rod-like structure and abundant hydroxyl groups of MCC-MnO2, the organized mesostructure of SA aerogels was reconstructed during the assembly of SA molecule chains, which gave rise to a significant enhancement in macroscopic performance of SA areogels. For instance, the functionalized and reconstructed MCC-MnO2/SA aerogels acquired a more than 70% increase in mechanical strength with an excellent deformation recovery. Furthermore, an almost double enhancement of removal capacity for metal ions (i.e., Cu2+ and Pb2+) and organic dyes (i.e., congo red and methylene blue) was obtained for MnO2/SA aerogels, with an 87% repossession of the pollutants removal performance after 5 operation cycles.

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Strong spin frustration and magnetism in kagomé antiferromagnets LnCu3(OH)6Br3 (Ln=Nd, Sm, and Eu) Jin-Qun Zhong(钟金群), Zhen-Wei Yu(余振伟), Xiao-Yu Yue(岳小宇), Yi-Yan Wang(王义炎), Hui Liang(梁慧), Yan Sun(孙燕), Dan-Dan Wu(吴丹丹), Zong-Ling Ding(丁宗玲), Jin Sun(孙进), Xue-Feng Sun(孙学峰), and Qiu-Ju Li(李秋菊) Chin. Phys. B, 2023, 32 (4): 047505.   DOI: 10.1088/1674-1056/acb9e8 Abstract （505）   HTML （159）    PDF （2462KB）（558）       Knowledge map    To study the effects of lanthanide ions on the geometrically frustrated antiferromagnets and their magnetic properties, we grew high-quality single crystals of $Ln$Cu$_{3}$(OH)$_{6}$Br$_{3}$ ($Ln={\rm Nd}$, Sm, and Eu) by hydrothermal method and studied their crystal structures and magnetic properties. The refinements of the crystal structure referred to the powder x-ray diffraction data show that $Ln$Cu$_{3}$(OH)$_{6}$Br$_{3}$ adopt a Kapellasite-type layer structure, which is isostructural to their chlorine analogue. Magnetic susceptibilities demonstrate that $Ln$Cu$_{3}$(OH)$_{6}$Br$_{3}$ have strong antiferromagnetic coupling and a pronounced magnetic frustration effect. Magnetization measurements indicate canted antiferromagnetic ordering of Cu$^{2+}$ ions around 16 K within the kagomé plane and weak ferromagnetic coupling. Moreover, shoulder-like anomalies in specific heat around 16 K could be a signature of emergent of magnetic ordering. The low-temperature negative magnetization and specific heat of $Ln$Cu$_{3}$(OH)$_{6}$Br$_{3}$ ($Ln={\rm Nd}$, Sm, and Eu) indicate that $Ln^{3+}$ ions induce more exotic magnetic ground state properties.

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Intrinsic electronic structure and nodeless superconducting gap of YBa2Cu3O7-δ observed by spatially-resolved laser-based angle resolved photoemission spectroscopy Shuaishuai Li(李帅帅), Taimin Miao(苗泰民), Chaohui Yin(殷超辉), Yinghao Li(李颖昊), Hongtao Yan(闫宏涛), Yiwen Chen(陈逸雯), Bo Liang(梁波), Hao Chen(陈浩), Wenpei Zhu(朱文培), Shenjin Zhang(张申金), Zhimin Wang(王志敏), Fengfeng Zhang(张丰丰), Feng Yang(杨峰), Qinjun Peng(彭钦军), Chengtian Lin(林成天), Hanqing Mao(毛寒青), Guodong Liu(刘国东), Zuyan Xu(许祖彦), Lin Zhao(赵林), and X J Zhou(周兴江) Chin. Phys. B, 2023, 32 (11): 117401.   DOI: 10.1088/1674-1056/acf498 Abstract （224）   HTML （10）    PDF （6820KB）（520）       Knowledge map    The spatially-resolved laser-based high-resolution angle resolved photoemission spectroscopy (ARPES) measurements have been performed on the optimally-doped YBa2Cu3O7-δ (Y123) superconductor. For the first time, we found the region from the cleaved surface that reveals clear bulk electronic properties. The intrinsic Fermi surface and band structures of Y123 were observed. The Fermi surface-dependent and momentum-dependent superconducting gap was determined which is nodeless and consistent with the d+is gap form.

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Room-temperature creation and manipulation of skyrmions in MgO/FeNiB/Mo multilayers Wen-Hui Liang(梁文会), Jian Su(苏鉴), Yu-Tong Wang(王雨桐), Ying Zhang(张颖), Feng-Xia Hu(胡凤霞), and Jian-Wang Cai(蔡建旺) Chin. Phys. B, 2023, 32 (12): 127504.   DOI: 10.1088/1674-1056/acf5d4 Abstract （435）   HTML （0）    PDF （6693KB）（516）       Knowledge map    Magnetic skyrmions in multilayer structures are considered as a new direction for the next generation of storage due to their small size, strong anti-interference ability, high current-driven mobility, and compatibility with existing spintronic technology. In this work, we present a tunable room temperature skyrmion platform based on multilayer stacks of MgO/FeNiB/Mo. We systematically studied the creation of magnetic skyrmions in MgO/FeNiB/Mo multilayer structures with perpendicular magnetic anisotropy (PMA). In these structures, the magnetic anisotropy changes from PMA to in-plane magnetic anisotropy (IMA) as the thickness of FeNiB layer increases. By adjusting the applied magnetic field and electric current, stable and high-density skyrmions can be obtained in the material system. The discovery of this material broadens the exploration of new materials for skyrmion and promotes the development of spintronic devices based on skyrmions.

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Observation of nonlinearity and heating-induced frequency shifts in cavity magnonics Wei-Jiang Wu(吴维江), Da Xu(徐达), Jie Qian(钱洁), Jie Li(李杰), Yi-Pu Wang(王逸璞), and Jian-Qiang You(游建强) Chin. Phys. B, 2022, 31 (12): 127503.   DOI: 10.1088/1674-1056/ac9b02 Abstract （573）   HTML （3）    PDF （1892KB）（498）       Knowledge map    When there is a certain amount of field inhomogeneity, the biased ferrimagnetic crystal can exhibit the higher-order magnetostatic (HMS) mode in addition to the uniform-precession Kittel mode. In cavity magnonics, we show the nonlinearity and heating-induced frequency shifts of the Kittel mode and HMS mode in a yttrium-iron-garnet (YIG) sphere. When the Kittel mode is driven to generate a certain number of excitations, the temperature of the whole YIG sample rises and the HMS mode can display an induced frequency shift, and vice versa. This cross effect provides a new method to study the magnetization dynamics and paves a way for novel cavity magnonic devices by including the heating effect as an operational degree of freedom.

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Enhanced phase sensitive amplification towards improving noise immunity Hui Guo(郭辉), Zhi Li(李治), Hengxin Sun(孙恒信), Kui Liu(刘奎), and Jiangrui Gao(郜江瑞) Chin. Phys. B, 2023, 32 (5): 054204.   DOI: 10.1088/1674-1056/acbdeb Abstract （479）   HTML （28）    PDF （1960KB）（493）       Knowledge map    Quantum states are essential resource for quantum-enhanced applications. Loss incurred in the distribution channel, however, dissipates the high signal-to-noise ratio advantage enjoyed by the squeezed state. Here, we first demonstrate noise immunity enhancement by using phase-sensitive amplifier (PSA) with measurement-based noiseless linear amplifier (MB-NLA). We explore the signal transfer capability with the amplifier in a noisy channel. The MB-NLA enhanced PSA has obvious suppression effect on channel noises, especially it has improvement for the noise contaminated signal. Better performance can be achieved by flexibly adjusting amplifier parameters. With the amplifier, it is promising to overcome the entanglement-distribution loss and show its superiority in squeezing based quantum sensing.

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Monolayer MoS2 of high mobility grown on SiO2 substrate by two-step chemical vapor deposition Jia-Jun Ma(马佳俊), Kang Wu(吴康), Zhen-Yu Wang(王振宇), Rui-Song Ma(马瑞松), Li-Hong Bao(鲍丽宏), Qing Dai(戴庆), Jin-Dong Ren(任金东), and Hong-Jun Gao(高鸿钧) Chin. Phys. B, 2022, 31 (8): 088105.   DOI: 10.1088/1674-1056/ac6737 Abstract （659）   HTML （20）    PDF （1277KB）（493）       Knowledge map    We report a novel two-step ambient pressure chemical vapor deposition (CVD) pathway to grow high-quality MoS2 monolayer on the SiO2 substrate with large crystal size up to 110 μm. The large specific surface area of the pre-synthesized MoO3 flakes on the mica substrate compared to MoO3 powder could dramatically reduce the consumption of the Mo source. The electronic information inferred from the four-probe scanning tunneling microscope (4P-STM) image explains the threshold voltage variations and the n-type behavior observed in the two-terminal transport measurements. Furthermore, the direct van der Pauw transport also confirms its relatively high carrier mobility. Our study provides a reliable method to synthesize high-quality MoS2 monolayer, which is confirmed by the direct 4P-STM measurement results. Such methodology is a key step toward the large-scale growth of transition metal dichalcogenides (TMDs) on the SiO2 substrate and is essential to further development of the TMDs-related integrated devices.

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Development of a cryogen-free dilution refrigerator Zhongqing Ji(姬忠庆), Jie Fan(樊洁), Jing Dong(董靖), Yongbo Bian(边勇波), and Zhi-Gang Cheng(程智刚) Chin. Phys. B, 2022, 31 (12): 120703.   DOI: 10.1088/1674-1056/ac9042 Abstract （497）   HTML （7）    PDF （1053KB）（491）       Knowledge map    With thermal fluctuation strongly suppressed, low temperature environment is essential for studies of condensed matter physics and developments of quantum technologies. Ultra-low temperature below 20 mK has demonstrated its importance and significance in physical sciences and information techniques. Dilution refrigeration is by far the best feasible and reliable method to generate and keep lattice temperature in this range. With a potential shortage of helium supply, cryogen-free dilution refrigerator (CFDR), eliminating the necessity of regular helium refill, becomes the main facility for the purpose of creating ultralow temperature environments. Here we describe our successful construction of a CFDR which reached a base temperature of around 10.9 mK for continuous circulation and 8.6 mK for single-shot operation. We describe its operating mechanism and the designs of key components, especially some unique designs including heat switch and alumina thermal link. Possible improvements in the future are also discussed.

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Bismuth doping enhanced tunability of strain-controlled magnetic anisotropy in epitaxial Y3Fe5O12(111) films Yunpeng Jia(贾云鹏), Zhengguo Liang(梁正国), Haolin Pan(潘昊霖), Qing Wang(王庆), Qiming Lv(吕崎鸣), Yifei Yan(严轶非), Feng Jin(金锋), Dazhi Hou(侯达之), Lingfei Wang(王凌飞), and Wenbin Wu(吴文彬) Chin. Phys. B, 2023, 32 (2): 027501.   DOI: 10.1088/1674-1056/ac67cc Abstract （694）   HTML （7）    PDF （893KB）（486）       Knowledge map    Y3Fe5O12 (YIG) and BiY2Fe5O12 (Bi:YIG) films were epitaxially grown on a series of (111)-oriented garnet substrates using pulsed laser deposition. Structural and ferromagnetic resonance characterizations demonstrated the high epitaxial quality, extremely low magnetic loss and coherent strain state in these films. Using these epitaxial films as model systems, we systematically investigated the evolution of magnetic anisotropy (MA) with epitaxial strain and chemical doping. For both the YIG and Bi:YIG films, the compressive strain tends to align the magnetic moment in the film plane while the tensile strain can compete with the demagnetization effect and stabilize perpendicular MA. We found that the strain-induced lattice elongation/compression along the out-of-plane [111] axis is the key parameter that determines the MA. More importantly, the strain-induced tunability of MA can be enhanced significantly by Bi doping; meanwhile, the ultralow damping feature persists. We clarified that the cooperation between strain and chemical doping could realize an effective control of MA in garnet-type ferrites, which is essential for spintronic applications.

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Atomic optical spatial mode extractor for vector beams based on polarization-dependent absorption Hong Chang(常虹), Xin Yang(杨欣), Jinwen Wang(王金文), Yan Ma(马燕), Xinqi Yang(杨鑫琪), Mingtao Cao(曹明涛), Xiaofei Zhang(张晓斐), Hong Gao(高宏), Ruifang Dong(董瑞芳), and Shougang Zhang(张首刚) Chin. Phys. B, 2023, 32 (3): 034207.   DOI: 10.1088/1674-1056/acac19 Abstract （389）   HTML （5）    PDF （8912KB）（471）       Knowledge map    Vector beams with spiral phase and spatially varying polarization profiles have many applications from optical micromanipulation to materials processing. Here, we propose and demonstrate an atomic spatial mode extracting scheme for the vector beam based on polarization-dependent absorption in the atom vapor. By employing the linear polarization pump beam which induces polarization sensitive absorption in the atomic ensemble, a counter-propagated weak probe vector beam is extracted by spatial absorption, and extracted part still maintains the original polarization and the vortex phase. The topological charges of the extracted mode are verified by interfering with the Gaussian beam, and it can be found that the orbital angular momentum is conserved in the extracting process. Our work will have potential applications in non-destructive spatial mode identification, and is also useful for studying higher-dimensional quantum information based on atomic ensembles.

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Combination of density-clustering and supervised classification for event identification in single-molecule force spectroscopy data Yongyi Yuan(袁泳怡), Jialun Liang(梁嘉伦), Chuang Tan(谭创), Xueying Yang(杨雪滢), Dongni Yang(杨东尼), and Jie Ma(马杰) Chin. Phys. B, 2023, 32 (10): 108702.   DOI: 10.1088/1674-1056/acf03e Abstract （434）   HTML （6）    PDF （2308KB）（464）       Knowledge map    Single-molecule force spectroscopy (SMFS) measurements of the dynamics of biomolecules typically require identifying massive events and states from large data sets, such as extracting rupture forces from force-extension curves (FECs) in pulling experiments and identifying states from extension-time trajectories (ETTs) in force-clamp experiments. The former is often accomplished manually and hence is time-consuming and laborious while the latter is always impeded by the presence of baseline drift. In this study, we attempt to accurately and automatically identify the events and states from SMFS experiments with a machine learning approach, which combines clustering and classification for event identification of SMFS (ACCESS). As demonstrated by analysis of a series of data sets, ACCESS can extract the rupture forces from FECs containing multiple unfolding steps and classify the rupture forces into the corresponding conformational transitions. Moreover, ACCESS successfully identifies the unfolded and folded states even though the ETTs display severe nonmonotonic baseline drift. Besides, ACCESS is straightforward in use as it requires only three easy-to-interpret parameters. As such, we anticipate that ACCESS will be a useful, easy-to-implement and high-performance tool for event and state identification across a range of single-molecule experiments.

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Tunable correlation in twisted monolayer-trilayer graphene Dongdong Ding(丁冬冬), Ruirui Niu(牛锐锐), Xiangyan Han(韩香岩), Zhuangzhuang Qu(曲壮壮), Zhiyu Wang(王知雨), Zhuoxian Li(李卓贤), Qianling Liu(刘倩伶), Chunrui Han(韩春蕊), and Jianming Lu(路建明) Chin. Phys. B, 2023, 32 (6): 067204.   DOI: 10.1088/1674-1056/acc8c3 Abstract （457）   HTML （13）    PDF （1531KB）（463）       Knowledge map    Flat-band physics of moiré superlattices, originally discovered in the celebrated twisted bilayer graphene, have recently been intensively explored in multilayer graphene systems that can be further controlled by electric field. In this work, we experimentally find the evidence of correlated insulators at half filling of the electron moiré band of twisted monolayer-trilayer graphene with a twist angle around 1.2°. Van Hove singularity (VHS), manifested as enhanced resistance and zero Hall voltage, is observed to be distinct in conduction and valence flat bands. It also depends on the direction and magnitude of the displacement fields, consistent with the asymmetric crystal structure. While the resistance ridges at VHS can be enhanced by magnetic fields, when they cross commensurate fillings of the moiré superlattice in the conduction band, the enhancement is so strong that signatures of correlated insulator appear, which may further develop into an energy gap depending on the correlation strength. At last, Fermi velocity derived from temperature coefficients of resistivity is compared between conduction and valence bands with different displacement fields. It is found that electronic correlation has a negative dependence on the Fermi velocity, which in turn could be used to quantify the correlation strength.

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Emergence of correlations in twisted monolayer-trilayer graphene heterostructures Zhang Zhou(周璋), Kenji Watanabe, Takashi Taniguchi, Xiao Lin(林晓), Jinhai Mao(毛金海), and Hong-Jun Gao(高鸿钧) Chin. Phys. B, 2023, 32 (9): 097203.   DOI: 10.1088/1674-1056/ace3a8 Abstract （426）   HTML （22）    PDF （1897KB）（458）       Knowledge map    Twisted bilayer graphene heterostructures have recently emerged as a well-established platform for studying strongly correlated phases, such as correlated insulating, superconducting, and topological states. Extending this notion to twisted multilayer graphene heterostructures has exhibited more diverse correlated phases, as some fundamental properties related to symmetry and band structures are correspondingly modified. Here, we report the observations of correlated states in twisted monolayer-trilayer (Bernal stacked) graphene heterostructures. Correlated phases at integer fillings of the moiré unit cell are revealed at a high displacement field and stabilized with a moderate magnetic field on the electron-doping side at a twist angle of 1.45°, where the lift of degeneracy at the integer fillings is observed in the Landau fan diagram. Our results demonstrate the effectiveness of moiré engineering in an extended structure and provide insights into electric-field tunable correlated phases.

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Remote entangling gate between a quantum dot spin and a transmon qubit mediated by microwave photons Xing-Yu Zhu(朱行宇), Le-Tian Zhu(朱乐天), Tao Tu(涂涛), and Chuan-Feng Li(李传锋) Chin. Phys. B, 2024, 33 (2): 020315.   DOI: 10.1088/1674-1056/ad1747 Abstract （415）   HTML （7）    PDF （729KB）（451）       Knowledge map    Spin qubits and superconducting qubits are promising candidates for realizing solid-state quantum information processors. Designing a hybrid architecture that combines the advantages of different qubits on the same chip is a highly desirable but challenging goal. Here we propose a hybrid architecture that utilizes a high-impedance SQUID array resonator as a quantum bus, thereby coherently coupling different solid-state qubits. We employ a resonant exchange spin qubit hosted in a triple quantum dot and a superconducting transmon qubit. Since this hybrid system is highly tunable, it can operate in a dispersive regime, where the interaction between the different qubits is mediated by virtual photons. By utilizing such interactions, entangling gate operations between different qubits can be realized in a short time of 30 ns with a fidelity of up to 96.5% under realistic parameter conditions. Further utilizing this interaction, remote entangled state between different qubits can be prepared and is robust to perturbations of various parameters. These results pave the way for exploring efficient fault-tolerant quantum computation on hybrid quantum architecture platforms.

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Image segmentation of exfoliated two-dimensional materials by generative adversarial network-based data augmentation Xiaoyu Cheng(程晓昱), Chenxue Xie(解晨雪), Yulun Liu(刘宇伦), Ruixue Bai(白瑞雪), Nanhai Xiao(肖南海), Yanbo Ren(任琰博), Xilin Zhang(张喜林), Hui Ma(马惠), and Chongyun Jiang(蒋崇云) Chin. Phys. B, 2024, 33 (3): 030703.   DOI: 10.1088/1674-1056/ad23d8 Abstract （444）   HTML （36）    PDF （1065KB）（451）       Knowledge map    Mechanically cleaved two-dimensional materials are random in size and thickness. Recognizing atomically thin flakes by human experts is inefficient and unsuitable for scalable production. Deep learning algorithms have been adopted as an alternative, nevertheless a major challenge is a lack of sufficient actual training images. Here we report the generation of synthetic two-dimensional materials images using StyleGAN3 to complement the dataset. DeepLabv3Plus network is trained with the synthetic images which reduces overfitting and improves recognition accuracy to over 90%. A semi-supervisory technique for labeling images is introduced to reduce manual efforts. The sharper edges recognized by this method facilitate material stacking with precise edge alignment, which benefits exploring novel properties of layered-material devices that crucially depend on the interlayer twist-angle. This feasible and efficient method allows for the rapid and high-quality manufacturing of atomically thin materials and devices.

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Periodic electron oscillation in coupled two-dimensional lattices Yan-Yan Lu(陆艳艳), Chao Wang(王超), Jin-Yi Jiang(将金益), Jie Liu(刘洁), and Jian-Xin Zhong(钟建新) Chin. Phys. B, 2023, 32 (7): 070306.   DOI: 10.1088/1674-1056/acce93 Abstract （391）   HTML （13）    PDF （1670KB）（441）       Knowledge map    We study the time evolution of electron wavepacket in the coupled two-dimensional (2D) lattices with mirror symmetry, utilizing the tight-binding Hamiltonian framework. We show analytically that the wavepacket of an electron initially located on one atomic layer in the coupled 2D square lattices exhibits a periodic oscillation in both the transverse and longitudinal directions. The frequency of this oscillation is determined by the strength of the interlayer hopping. Additionally, we provide numerical evidence that a damped periodic oscillation occurs in the coupled 2D disordered lattices with degree of disorder W, with the decay time being inversely proportional to the square of W and the frequency change being proportional to the square of W, which is similar to the case in the coupled 1D disordered lattices. Our numerical results further confirm that the periodic and damped periodic electron oscillations are universal, independent of lattice geometry, as demonstrated in AA-stacked bilayer and tri-layer graphene systems. Unlike the Bloch oscillation driven by electric fields, the periodic oscillation induced by interlayer coupling does not require the application of an electric field, has an ultrafast periodicity much shorter than the electron decoherence time in real materials, and can be tuned by adjusting the interlayer coupling. Our findings pave the way for future observation of periodic electron oscillation in material systems at the atomic scale.