首页|Optical spectrum of ferrovalley materials:A case study of Janus H-VSSe

Optical spectrum of ferrovalley materials:A case study of Janus H-VSSe

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As opposed to the prototypical MoS2 with centroasymmetry,Janus ferrovalley materials such as H-VSSe are less symmetric with the mirror symmetry and time reversal symmetry broken,and hence possess spontaneous valley polarization and strong ferroelasticity.The optical transition is an important means to excite the valley carriers.We investigate the optical spectrum of H-VSSe by using the many-body perturbation-based GW approach and solving the Bethe-Salpeter equation(BSE)to include the electron-hole interactions.It is found that after the GW correction,the band gaps of the quasiparticle bands are much larger than those obtained by the normal density functional theory.The system is ferromagnetic and the valley gaps become non-degenerate due to spin-orbit coupling(SOC).The position of the lowest BSE peak is much lower than the quasiparticle band gap,indicating that the excitonic effect is large.The peak is split into two peaks by the SOC.The binding energy difference between these two BSE peaks is about the same as the difference between the inequivalent valley gaps.Our results show that in Janus H-VSSe the two lowest exciton peaks are from the two inequivalent valleys with different gaps,in contrast to the A and B exciton peaks of MoS2 which are from the same valley.

valleytronicsfirst-principles calculationsGW approach and Bethe-Salpeter equation(GW-BSE)excitonic effects

罗朝波、刘文超、彭向阳

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Hunan Key Laboratory for Micro-Nano Energy Materials and Devices,School of Physics and Optoelectronics,Xiangtan University,Xiangtan 411105,China

National Natural Science Foundation of ChinaPostgraduate Scientific Research Innovation Project of Hunan Province of China

11874315CX20220663

2024

10.1088/1674-1056/acf660

中国物理B(英文版)
中国物理学会和中国科学院物理研究所

中国物理B(英文版)

CSTPCDEI
影响因子：0.995
ISSN：1674-1056
年,卷(期)：2024.33(1)
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