The valley of transition metal dichalcogenides provides an additional platform to manipulate spin due to its unique selection rule. Normally, intralayer optical transitions in magnetic field show a Zeeman splitting with g factor of about −4. Here we report remarkable valley Zeeman effect exhibited by splitting of excitonic emission in a bilayer WS2, with a value of g factor as large as −16.5. The observed large g factor results from the interlayer recombination, as the conduction band and valence band are modified in opposite directions by magnetic field in different layers. The interlayer recombination is due to the defect induced inversion symmetry breaking, which is theoretically not accessible in ideal bilayer WS2 with inversion symmetry. Large g factor of interlayer emission offers potential benefits for future optical spin control and detection.
Cite
@article{arxiv.1903.09329,
title = {Large g factor in bilayer WS$_2$ flakes},
author = {Sibai Sun and Yang Yu and Jianchen Dang and Kai Peng and Xin Xie and Feilong Song and Chenjiang Qian and Shiyao Wu and Hassan Ali and Jing Tang and Jingnan Yang and Shan Xiao and Shilu Tian and Meng Wang and Xinyan Shan and M. A. Rafiq and Can Wang and Xiulai Xu},
journal= {arXiv preprint arXiv:1903.09329},
year = {2019}
}