Control of valley polarization in monolayer MoS2 by optical helicity

Control of valley polarization in monolayer MoS2 by optical helicity

| Kin Fai Mak, Keliang He, Jie Shan, and Tony F. Heinz
The paper demonstrates the dynamic control of valley polarization in monolayer MoS₂ using optical helicity. Monolayer MoS₂, a two-dimensional (2D) non-centrosymmetric crystal with direct energy gaps at two valleys, exhibits valley-polarized electronic properties due to broken inversion symmetry. The authors show that circularly polarized light can be used to selectively excite one valley over the other, achieving complete valley polarization that persists for over 1 ns. This effect is attributed to the coupling of valley and spin degrees of freedom in monolayer MoS₂, which is not present in bilayer MoS₂ due to its indirect band gap and restored inversion symmetry. The robustness of this phenomenon across different substrates and temperatures suggests its potential for electronic and optoelectronic applications in valley-based devices. The study provides a new approach to control valley polarization in solids, opening up avenues for fundamental research and practical applications.The paper demonstrates the dynamic control of valley polarization in monolayer MoS₂ using optical helicity. Monolayer MoS₂, a two-dimensional (2D) non-centrosymmetric crystal with direct energy gaps at two valleys, exhibits valley-polarized electronic properties due to broken inversion symmetry. The authors show that circularly polarized light can be used to selectively excite one valley over the other, achieving complete valley polarization that persists for over 1 ns. This effect is attributed to the coupling of valley and spin degrees of freedom in monolayer MoS₂, which is not present in bilayer MoS₂ due to its indirect band gap and restored inversion symmetry. The robustness of this phenomenon across different substrates and temperatures suggests its potential for electronic and optoelectronic applications in valley-based devices. The study provides a new approach to control valley polarization in solids, opening up avenues for fundamental research and practical applications.
Reach us at info@study.space
[slides] Control of valley polarization in monolayer MoS2 by optical helicity. | StudySpace