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Published in last 1 year |  In last 2 years |  In last 3 years |  All Please wait a minute... For selected: Download citations EndNote Ris BibTeX Toggle thumbnails Select Direct visualization of structural defects in 2D semiconductors Yutuo Guo(郭玉拓), Qinqin Wang(王琴琴), Xiaomei Li(李晓梅), Zheng Wei(魏争), Lu Li(李璐), Yalin Peng(彭雅琳), Wei Yang(杨威), Rong Yang(杨蓉), Dongxia Shi(时东霞), Xuedong Bai(白雪冬), Luojun Du(杜罗军), and Guangyu Zhang(张广宇) Chin. Phys. B, 2022, 31 (7): 076105.   DOI: 10.1088/1674-1056/ac6738 Abstract （771）   HTML （43）    PDF （4731KB）（479）       Knowledge map    Direct visualization of the structural defects in two-dimensional (2D) semiconductors at a large scale plays a significant role in understanding their electrical/optical/magnetic properties, but is challenging. Although traditional atomic resolution imaging techniques, such as transmission electron microscopy and scanning tunneling microscopy, can directly image the structural defects, they provide only local-scale information and require complex setups. Here, we develop a simple, non-invasive wet etching method to directly visualize the structural defects in 2D semiconductors at a large scale, including both point defects and grain boundaries. Utilizing this method, we extract successfully the defects density in several different types of monolayer molybdenum disulfide samples, providing key insights into the device functions. Furthermore, the etching method we developed is anisotropic and tunable, opening up opportunities to obtain exotic edge states on demand. Select 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 （640）   HTML （7）    PDF （893KB）（454）       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. Select 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 （635）   HTML （24）    PDF （7614KB）（554）       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. Select 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 （634）   HTML （20）    PDF （1277KB）（463）       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. Select Experimental observation of pseudogap in a modulation-doped Mott insulator: Sn/Si(111)-(√30×√30)R30° Yan-Ling Xiong(熊艳翎), Jia-Qi Guan(关佳其), Rui-Feng Wang(汪瑞峰), Can-Li Song(宋灿立), Xu-Cun Ma(马旭村), and Qi-Kun Xue(薛其坤) Chin. Phys. B, 2022, 31 (6): 067401.   DOI: 10.1088/1674-1056/ac65f2 Abstract （599）   HTML （11）    PDF （2064KB）（246）       Knowledge map    Unusual quantum phenomena usually emerge upon doping Mott insulators. Using a molecular beam epitaxy system integrated with cryogenic scanning tunneling microscope, we investigate the electronic structure of a modulation-doped Mott insulator Sn/Si(111)-($\sqrt{3}\times \sqrt{3})R$30$^\circ$. In underdoped regions, we observe a universal pseudogap opening around the Fermi level, which changes little with the applied magnetic field and the occurrence of Sn vacancies. The pseudogap gets smeared out at elevated temperatures and alters in size with the spatial confinement of the Mott insulating phase. Our findings, along with the previously observed superconductivity at a higher doping level, are highly reminiscent of the electronic phase diagram in the doped copper oxide compounds. Select 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 （591）   HTML （11）    PDF （3465KB）（629）       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. Select High-pressure study of topological semimetals XCd2Sb2 (X = Eu and Yb) Chuchu Zhu(朱楚楚), Hao Su(苏豪), Erjian Cheng(程二建), Lin Guo(郭琳), Binglin Pan(泮炳霖), Yeyu Huang(黄烨煜), Jiamin Ni(倪佳敏), Yanfeng Guo(郭艳峰), Xiaofan Yang(杨小帆), and Shiyan Li(李世燕) Chin. Phys. B, 2022, 31 (7): 076201.   DOI: 10.1088/1674-1056/ac7212 Abstract （536）   HTML （19）    PDF （1805KB）（275）       Knowledge map    Topological materials have aroused great interest in recent years, especially when magnetism is involved. Pressure can effectively tune the topological states and possibly induce superconductivity. Here we report the high-pressure study of topological semimetals $X$Cd$_{2}$Sb$_{2}$ ($X = {\rm Eu} $ and Yb), which have the same crystal structure. In antiferromagnetic (AFM) Weyl semimetal EuCd$_{2}$Sb$_{2}$, the Néel temperature (${T}_{\rm N}$) increases from 7.4 K at ambient pressure to 50.9 K at 14.9 GPa. When pressure is above 14.9 GPa, the AFM peak of resistance disappears, indicating a non-magnetic state. In paramagnetic Dirac semimetal candidate YbCd$_{2}$Sb$_{2}$, pressure-induced superconductivity appears at 1.94 GPa, then ${ T}_{\rm c}$ reaches to a maximum of 1.67 K at 5.22 GPa and drops to zero at about 30 GPa, displaying a dome-shaped temperature-pressure phase diagram. High-pressure x-ray diffraction measurement demonstrates that a crystalline-to-amorphous phase transition occurs at about 16 GPa in YbCd$_{2}$Sb$_{2}$, revealing the robustness of pressure-induced superconductivity against structural instability. Similar structural phase transition may also occur in EuCd$_{2}$Sb$_{2}$, causing the disappearance of magnetism. Our results show that $X$Cd$_{2}$Sb$_{2}$ ($X = {\rm Eu}$ and Yb) is a novel platform for exploring the interplay among magnetism, topology, and superconductivity. Select Slight Co-doping tuned magnetic and electric properties on cubic BaFeO3 single crystal Shijun Qin(覃湜俊), Bowen Zhou(周博文), Zhehong Liu(刘哲宏), Xubin Ye(叶旭斌), Xueqiang Zhang(张雪强), Zhao Pan(潘昭), and Youwen Long(龙有文) Chin. Phys. B, 2022, 31 (9): 097503.   DOI: 10.1088/1674-1056/ac7549 Abstract （535）   HTML （20）    PDF （2095KB）（394）       Knowledge map    The single crystal of cubic perovskite BaFeO$_{3}$ shows multiple magnetic transitions and external stimulus sensitive magnetism. In this paper, a 5%-Co-doped BaFeO$_{3}$ (i.e. BaFe$_{0.95}$Co$_{0.05}$O$_{3})$ single crystal was grown by combining floating zone methods with high-pressure techniques. Such a slight Co doping has little effect on crystal structure, but significantly changes the magnetism from the parent antiferromagnetic ground state to a ferromagnetic one with the Curie temperature $T_{\rm C} \approx 120$ K. Compared with the parent BaFeO$_{3}$ at the induced ferromagnetic state, the saturated magnetic moment of the doped BaFe$_{0.95}$Co$_{0.05}$O$_{3}$ increases by about 10% and reaches 3.64 $\mu_{\rm B}$/f.u. Resistivity and specific heat measurements show that the ferromagnetic ordering favors metallic-like electrical transport behavior for BaFe$_{0.95}$Co$_{0.05}$O$_{3}$. The present work indicates that Co-doping is an effective method to tune the magnetic and electric properties for the cubic perovskite phase of BaFeO$_{3}$. Select Experimental realization of two-dimensional single-layer ultracold gases of 87Rb in an accordion lattice Liangwei Wang(王良伟), Kai Wen(文凯), Fangde Liu(刘方德), Yunda Li(李云达), Pengjun Wang(王鹏军), Lianghui Huang(黄良辉), Liangchao Chen(陈良超), Wei Han(韩伟), Zengming Meng(孟增明), and Jing Zhang(张靖) Chin. Phys. B, 2022, 31 (10): 103401.   DOI: 10.1088/1674-1056/ac873c Abstract （530）   HTML （18）    PDF （1293KB）（356）       Knowledge map    We experimentally realize two-dimensional (2D) single-layer ultracold gases of 87Rb by dynamically tuning the periodicity of a standing wave, known as accordion lattice. In order to load 87Rb Bose—Einstein condensate into single dark fringe node of the blue detuning optical lattice, we reduce the lattice periodicity from 26.7 μ to 3.5 μ with the help of an acousto-optic deflector (AOD) to compress the three-dimensional BEC adiabatically into a flat and uniform quasi-2D single-layer. We describe the experimental procedure of the atoms loading into the accordion lattice in detail and present the characteristics of the quasi-2D ultracold gases. This setup provides an important platform for studying in- and out-of equilibrium physics, phase transition and 2D topological matter. Select Precisely controlling the twist angle of epitaxial MoS2/graphene heterostructure by AFM tip manipulation Jiahao Yuan(袁嘉浩), Mengzhou Liao(廖梦舟), Zhiheng Huang(黄智恒), Jinpeng Tian(田金朋), Yanbang Chu(褚衍邦), Luojun Du(杜罗军), Wei Yang(杨威), Dongxia Shi(时东霞), Rong Yang(杨蓉), and Guangyu Zhang(张广宇) Chin. Phys. B, 2022, 31 (8): 087302.   DOI: 10.1088/1674-1056/ac720e Abstract （530）   HTML （5）    PDF （5416KB）（216）       Knowledge map    Two-dimensional (2D) moiré materials have attracted a lot of attention and opened a new research frontier of twistronics due to their novel physical properties. Although great progress has been achieved, the inability to precisely and reproducibly manipulate the twist angle hinders the further development of twistronics. Here, we demonstrated an atomic force microscope (AFM) tip manipulation method to control the interlayer twist angle of epitaxial MoS2/graphene heterostructure with an ultra-high accuracy better than 0.1°. Furthermore, conductive AFM and spectroscopic characterizations were conducted to show the effects of the twist angle on moiré pattern wavelength, phonons and excitons. Our work provides a technique to precisely control the twist angle of 2D moiré materials, enabling the possibility to establish the phase diagrams of moiré physics with twist angle. Select Conservation of the particle-hole symmetry in the pseudogap state in optimally-doped Bi2Sr2CuO6+δ superconductor Hongtao Yan(闫宏涛), Qiang Gao(高强), Chunyao Song(宋春尧), Chaohui Yin(殷超辉), Yiwen Chen(陈逸雯), Fengfeng Zhang(张丰丰), Feng Yang(杨峰), Shenjin Zhang(张申金), Qinjun Peng(彭钦军), Guodong Liu(刘国东), Lin Zhao(赵林), Zuyan Xu(许祖彦), and X. J. Zhou(周兴江) Chin. Phys. B, 2022, 31 (8): 087401.   DOI: 10.1088/1674-1056/ac7214 Abstract （520）   HTML （9）    PDF （3004KB）（179）       Knowledge map    The pseudogap state is one of the most enigmatic characteristics in the anomalous normal state properties of the high temperature cuprate superconductors. A central issue is to reveal whether there is a symmetry breaking and which symmetries are broken across the pseudogap transition. By performing high resolution laser-based angle-resolved photoemission measurements on the optimally-doped Bi2Sr1.6La0.4CuO6+δ superconductor, we report the observations of the particle-hole symmetry conservation in both the superconducting state and the pseudogap state along the entire Fermi surface. These results provide key insights in understanding the nature of the pseudogap and its relation with high temperature superconductivity. Select Charge density wave states in phase-engineered monolayer VTe2 Zhi-Li Zhu(朱知力), Zhong-Liu Liu(刘中流), Xu Wu(武旭), Xuan-Yi Li(李轩熠), Jin-An Shi(时金安), Chen Liu(刘晨), Guo-Jian Qian(钱国健), Qi Zheng(郑琦), Li Huang(黄立), Xiao Lin(林晓), Jia-Ou Wang(王嘉欧), Hui Chen(陈辉), Wu Zhou(周武), Jia-Tao Sun(孙家涛), Ye-Liang Wang(王业亮), and Hong-Jun Gao(高鸿钧) Chin. Phys. B, 2022, 31 (7): 077101.   DOI: 10.1088/1674-1056/ac6739 Abstract （511）   HTML （16）    PDF （2796KB）（247）       Knowledge map    Charge density wave (CDW) strongly affects the electronic properties of two-dimensional (2D) materials and can be tuned by phase engineering. Among 2D transitional metal dichalcogenides (TMDs), VTe$_{2}$ was predicted to require small energy for its phase transition and shows unexpected CDW states in its T-phase. However, the CDW state of H-VTe$_{2}$ has been barely reported. Here, we investigate the CDW states in monolayer (ML) H-VTe$_{2}$, induced by phase-engineering from T-phase VTe$_{2}$. The phase transition between T- and H-VTe$_{2}$ is revealed with x-ray photoelectron spectroscopy (XPS) and scanning transmission electron microscopy (STEM) measurements. For H-VTe$_{2}$, scanning tunneling microscope (STM) and low-energy electron diffraction (LEED) results show a robust $2\sqrt 3 \times 2\sqrt 3 $ CDW superlattice with a transition temperature above 450 K. Our findings provide a promising way for manipulating the CDWs in 2D materials and show great potential in its application of nanoelectronics. Select Switching plasticity in compensated ferrimagnetic multilayers for neuromorphic computing Weihao Li(李伟浩), Xiukai Lan(兰修凯), Xionghua Liu(刘雄华), Enze Zhang(张恩泽), Yongcheng Deng(邓永城), and Kaiyou Wang(王开友) Chin. Phys. B, 2022, 31 (11): 117106.   DOI: 10.1088/1674-1056/ac89dd Abstract （504）   HTML （15）    PDF （2967KB）（296）       Knowledge map    Current-induced multilevel magnetization switching in ferrimagnetic spintronic devices is highly pursued for the application in neuromorphic computing. In this work, we demonstrate the switching plasticity in Co/Gd ferrimagnetic multilayers where the binary states magnetization switching induced by spin-orbit toque can be tuned into a multistate one as decreasing the domain nucleation barrier. Therefore, the switching plasticity can be tuned by the perpendicular magnetic anisotropy of the multilayers and the in-plane magnetic field. Moreover, we used the switching plasticity of Co/Gd multilayers for demonstrating spike timing-dependent plasticity and sigmoid-like activation behavior. This work gives useful guidance to design multilevel spintronic devices which could be applied in high-performance neuromorphic computing. Select Structure of continuous matrix product operator for transverse field Ising model: An analytic and numerical study Yueshui Zhang(张越水) and Lei Wang(王磊) Chin. Phys. B, 2022, 31 (11): 110205.   DOI: 10.1088/1674-1056/ac8a8f Abstract （472）   HTML （18）    PDF （1049KB）（336）       Knowledge map    We study the structure of the continuous matrix product operator (cMPO)[1] for the transverse field Ising model (TFIM). We prove TFIM's cMPO is solvable and has the form $T=\rm{e}^{-\frac{1}{2}\hat{H}_{\rm F}}$. $\hat{H}_{\rm F}$ is a non-local free fermionic Hamiltonian on a ring with circumference $\beta$, whose ground state is gapped and non-degenerate even at the critical point. The full spectrum of $\hat{H}_{\rm F}$ is determined analytically. At the critical point, our results verify the state-operator-correspondence[2] in the conformal field theory (CFT). We also design a numerical algorithm based on Bloch state ansatz to calculate the low-lying excited states of general (Hermitian) cMPO. Our numerical calculations coincide with the analytic results of TFIM. In the end, we give a short discussion about the entanglement entropy of cMPO's ground state. Select 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 （472）   HTML （159）    PDF （2462KB）（533）       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. Select Uniaxial stress effect on quasi-one-dimensional Kondo lattice CeCo2Ga8 Kangqiao Cheng(程康桥), Binjie Zhou(周斌杰), Cuixiang Wang(王翠香), Shuo Zou(邹烁), Yupeng Pan(潘宇鹏), Xiaobo He(何晓波), Jian Zhang(张健), Fangjun Lu(卢方君), Le Wang(王乐), Youguo Shi(石友国), and Yongkang Luo(罗永康) Chin. Phys. B, 2022, 31 (6): 067104.   DOI: 10.1088/1674-1056/ac6339 Abstract （471）   HTML （6）    PDF （1321KB）（203）       Knowledge map    Quantum critical phenomena in the quasi-one-dimensional limit remain an open issue. We report the uniaxial stress effect on the quasi-one-dimensional Kondo lattice CeCo$_2$Ga$_8$ by electric transport and AC heat capacity measurements. CeCo$_2$Ga$_8$ is speculated to sit in close vicinity but on the quantum-disordered side of a quantum critical point. Upon compressing the ${c}$ axis, parallel to the Ce-Ce chain, the onset of coherent Kondo effect is enhanced. In contrast, the electronic specific heat diverges more rapidly at low temperature when the intra-chain distance is elongated by compressions along ${a}$ or ${b}$ axis. These results suggest that a tensile intra-chain strain ($\varepsilon_c >0$) pushes CeCo$_2$Ga$_8$ closer to the quantum critical point, while a compressive intra-chain strain ($\varepsilon_c<0$) likely causes departure. Our work provides a rare paradigm of manipulation near a quantum critical point in a quasi-1D Kondo lattice by uniaxial stress, and paves the way for further investigations on the unique feature of quantum criticality in the quasi-1D limit. Select Atomistic simulations of graphene origami: Dynamics and kinetics Panpan Zhang(张盼盼), Haihong Jia(贾海洪), Yan-Fang Zhang(张艳芳), and Shixuan Du(杜世萱) Chin. Phys. B, 2023, 32 (8): 087107.   DOI: 10.1088/1674-1056/acd527 Abstract （469）   HTML （8）    PDF （2692KB）（408）       Knowledge map    Origami offers two-dimensional (2D) materials with great potential for applications in flexible electronics, sensors, and smart devices. However, the dynamic process, which is crucial to construct origami, is too fast to be characterized by using state-of-the-art experimental techniques. Here, to understand the dynamics and kinetics at the atomic level, we explore the edge effects, structural and energy evolution during the origami process of an elliptical graphene nano-island (GNI) on a highly ordered pyrolytic graphite (HOPG) substrate by employing steered molecular dynamics simulations. The results reveal that a sharper armchair edge is much easier to be lifted up and realize origami than a blunt zigzag edge. The potential energy of the GNI increases at the lifting-up stage, reaches the maximum at the beginning of the bending stage, decreases with the formation of van der Waals overlap, and finally reaches an energy minimum at a half-folded configuration. The unfolding barriers of elliptical GNIs with different lengths of major axis show that the major axis should be larger than 242 Å to achieve a stable single-folded structure at room temperature. These findings pave the way for pursuing other 2D material origami and preparing origami-based nanodevices. Select Magnetic triangular bubble lattices in bismuth-doped yttrium iron garnet Tao Lin(蔺涛), Chengxiang Wang(王承祥), Zhiyong Qiu(邱志勇), Chao Chen(陈超), Tao Xing(邢弢), Lu Sun(孙璐), Jianhui Liang(梁建辉), Yizheng Wu(吴义政), Zhong Shi(时钟), and Na Lei(雷娜) Chin. Phys. B, 2023, 32 (2): 027505.   DOI: 10.1088/1674-1056/aca604 Abstract （454）   HTML （13）    PDF （2430KB）（337）       Knowledge map    Magnetic bubbles have again become a subject of significant attention following the experimental observation of topologically nontrivial magnetic skyrmions. In recent work, tailoring the shape of the bubbles is considered a key factor for their dynamics in spintronic devices. In addition to the reported circular, elliptical, and square bubbles, here we observe triangular bubble domains in bismuth-doped yttrium iron garnet (Bi-YIG) using Kerr microscopy. The bubble domains evolve from discrete circular to latticed triangular and hexagonal shapes. Further, the orientation of the triangular bubbles in the hexagonal lattices can be flipped by decreasing the magnetic field. The sixfold in-plane magnetic anisotropy of Bi-YIG(111) crystal, which is presumably the mechanism underlying the triangular shape of the bubbles, is measured as 1179 erg/cm3. The study of the morphologies of topologically trivial bubbles in YIG offers insight into nontrivial spin textures, which is appealing for future spintronic applications. Select 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 （453）   HTML （28）    PDF （1960KB）（462）       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. Select A novel demodulation method for transmission using nitrogen-vacancy-based solid-state quantum sensor Ruixin Bai(白瑞昕), Xinyue Zhu(朱欣岳), Fan Yang(杨帆), Tianran Gao(高天然), Ziran Wang(汪子然), Linyan Yu(虞林嫣), Jinfeng Wang(汪晋锋), Li Zhou(周力), and Guanxiang Du(杜关祥) Chin. Phys. B, 2022, 31 (7): 074203.   DOI: 10.1088/1674-1056/ac5618 Abstract （451）   HTML （3）    PDF （1083KB）（87）       Knowledge map    Diamond based quantum sensing is a fast-emerging field with both scientific and technological significance. The nitrogen-vacancy (NV) center, a crystal defect in diamond, has become a unique object for microwave sensing applications due to its excellent stability, long spin coherence time, and optical properties at ambient condition. In this work, we use diamond NV center as atomic receiver to demodulate on-off keying (OOK) signal transmitted in broad frequency range (2 GHz-14 GHz in a portable benchtop setup). We proposed a unique algorithm of voltage discrimination and demonstrated audio signal transceiving with fidelity above 99%. This diamond receiver is attached to the end of a tapered fiber, having all optic nature, which will find important applications in data transmission tasks under extreme conditions such as strong electromagnetic interference, high temperatures, and high corrosion. page Page 1 of 8 Total 145 records First page Prev page Next page Last page