2D materials, such as gapped graphene, monolayer TMDs and Weyl semimetals, possess interesting Berry curvature effects (a geometric effect of their band structures). We study the optical and transport properties of these materials arisen from the Berry curvature effects. We also explore the valley degree of freedom of electrons in these materials as a new type of information carrier for electronic and optoelectronic devices.
Reviews
Photonics and optoelectronics of two-dimensional semiconductor transition metal dichalcogenides
K. F. Mak and J. Shan, Nature Photon. 10, 216-226 (2016).
Light-valley interactions in 2D semiconductors
K. F. Mak, D. Xiao, and J. Shan, Nature Photon. 12, 451-460 (2018).
Valley dependent optical properties
Control of valley polarization in monolayer MoS2 by optical helicity
K. F. Mak, K. He, J. Shan, and T.F. Heinz, Nature Nanotech. 7, 494–498 (2012).
Valley- and spin-polarized Landau levels in monolayer WSe2
Z. Wang, J. Shan, and K. F. Mak, Nature Nanotech. 12, 144–149 (2017).
Valley dependent transport properties
The valley Hall effect in MoS2 transistors
K. F. Mak, K. L. McGill, J. Park, and P. L. McEuen, Science 344, 1489-1492 (2014).
Electrical control of the valley Hall effect in bilayer MoS2 transistors
J. Lee, K. F. Mak, and J. Shan, Nature Nanotech. 11, 421-425 (2016).
Valley magnetoelectricity in single-layer MoS2
J. Lee, Z. Wang, H. Xie, K. F. Mak, and J. Shan, Nature Mater. 16, 887-891 (2017).
Nonlinear anomalous transport
Nonlinear anomalous Hall effect in few-layer WTe2
K. Kang, T. Li, E. Sohn, J. Shan, and K. F. Mak, Nature Mater. 18, 324-328 (2019).