Content of TOPICIAL REVIEW—Valleytronics in our journal

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 Gate-field control of valley polarization in valleytronics Ting-Ting Zhang(张婷婷), Yilin Han(韩依琳), Run-Wu Zhang(张闰午), and Zhi-Ming Yu(余智明) Chin. Phys. B, 2024, 33 (6): 067303.   DOI: 10.1088/1674-1056/ad401a Abstract （184）   HTML （2）    PDF （1595KB）（202）       Knowledge map    Valleytronics materials are a kind of special semiconductors which can host multiple symmetry-connected and well-separated electron or hole pockets in the Brillouin zone when the system is slightly n or p doped. Since the low-energy particles residing in these pockets generally are not easily scattered to each other by small perturbations, they are endowed with an additional valley degree of freedom. Analogous to spin, the valley freedom can be used to process information, leading to the concept of valleytronics. The prerequisite for valleytronics is the generation of valley polarization. Thus, a focus in this field is achieving the electric generation of valley polarization, especially the static generation by the gate electric field alone. In this work, we briefly review the latest progress in this research direction, focusing on the concepts of the couplings between valley and layer, i.e., the valley-layer coupling which permits the gate-field control of the valley polarization, the couplings between valley, layer, and spin in magnetic systems, the physical properties, the novel designing schemes for electronic devices, and the material realizations of the gate-controlled valleytronics materials. Select Valley polarization in transition metal dichalcogenide layered semiconductors: Generation, relaxation, manipulation and transport Hui Ma(马惠), Yaojie Zhu(朱耀杰), Yulun Liu(刘宇伦), Ruixue Bai(白瑞雪), Xilin Zhang(张喜林), Yanbo Ren(任琰博), and Chongyun Jiang(蒋崇云) Chin. Phys. B, 2023, 32 (10): 107201.   DOI: 10.1088/1674-1056/ace160 Abstract （340）   HTML （8）    PDF （7199KB）（266）       Knowledge map    In recent years, valleytronics researches based on 2D semiconducting transition metal dichalcogenides have attracted considerable attention. On the one hand, strong spin-orbit interaction allows the presence of spin-valley coupling in this system, which provides spin addressable valley degrees of freedom for information storage and processing. On the other hand, large exciton binding energy up to hundreds of meV enables excitons to be stable carriers of valley information. Valley polarization, marked by an imbalanced exciton population in two inequivalent valleys (+$K$ and -$K$), is the core of valleytronics as it can be utilized to store binary information. Motivated by the potential applications, we present a thorough overview of the recent advancements in the generation, relaxation, manipulation, and transport of the valley polarization in nonmagnetic transition metal dichalcogenide layered semiconductors. We also discuss the development of valleytronic devices and future challenges in this field. Select Perspectives of spin-valley locking devices Lingling Tao(陶玲玲) Chin. Phys. B, 2023, 32 (10): 107306.   DOI: 10.1088/1674-1056/acc809 Abstract （388）   HTML （8）    PDF （5558KB）（314）       Knowledge map    Valleytronics is an emerging field of research which utilizes the valley degree of freedom to encode information. However, it is technically nontrivial to produce a stable valley polarization and to achieve efficient control and manipulation of valleys. Spin-valley locking refers to the coupling between spin and valley degrees of freedom in the materials with large spin-orbit coupling (SOC) and enables the manipulation of valleys indirectly through controlling spins. Here, we review the recent advances in spin-valley locking physics and outline possible device implications. In particular, we focus on the spin-valley locking induced by SOC and external electric field in certain two-dimensional materials with inversion symmetry and demonstrate the intriguing switchable valley-spin polarization, which can be utilized to design the promising electronic devices, namely, valley-spin valves and logic gates.