Author:
Wang Kai-Tong,Wang Hui,Xu Fuming,Yu Yunjin,Wei Yadong
Abstract
Abstract
Monolayer
M
o
S
2
is a typical valleytronic material with valley-spin locked valence bands. We numerically investigate the valley-spin polarized current in monolayer
M
o
S
2
via adiabatic electron pumping. By introducing an exchange field to break the energy degeneracy of monolayer
M
o
S
2
, the top of its valence bands is valley-spin polarized and tunable by the exchange field. A device with spin-up polarized left lead, spin-down polarized right lead, and untuned central region is constructed through applying different exchange fields in the corresponding regions. Then, equal amount of pumped currents with opposite valley-spin polarization are simultaneously generated in the left and right leads when periodically varying two pumping potentials. Numerical results show that the phase difference between the pumping potentials can change the direction and hence polarization of the pumped currents. It is found that the pumped current exhibits resonant behavior in the valley-spin locked energy window, which depends strongly on the system size and is enhanced to resonant current peaks at certain system lengths. More importantly, the pumped current periodically oscillates as a function of the system length, which is closely related to the oscillation of transmission. The effects of other system parameters, such as the pumping amplitude and the static potential, are also thoroughly discussed.
Funder
The Key Scientific and Technological Projects in Henan Province
National Natural Science Foundation of China
Natural Science Foundation of Shenzhen
Outstanding Youth Foundation of Henan Scientific Committee
Subject
General Physics and Astronomy
Cited by
3 articles.
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