Valley-selective circular dichroism of monolayer molybdenum disulphide

By Ting Cao, Gang Wang, W. Han, H. Ye, Chuanrui Zhu, Jun-ren Shi, Q. Niu, P. Tan, E. Wang, Baoli Liu and 1 more. Nature Communications, 2011

2,311 citations recorded by the source corpus.

A two-dimensional honeycomb lattice harbours a pair of inequivalent valleys in the k-space electronic structure, in the vicinities of the vertices of a hexagonal Brillouin zone, K±. It is particularly appealing to exploit this emergent degree of freedom of charge carriers, in what is termed 'valleytronics'. The physics of valleys mimics that of spin, and will make possible devices, analogous to spintronics, such as valley filter and valve, and optoelectronic Hall devices, all very promising for next-generation electronics. The key challenge lies with achieving valley polarization, of which a convincing demonstration in a two-dimensional honeycomb structure remains evasive. Here we show, using first principles calculations, that monolayer molybdenum disulphide is an ideal material for valleytronics, for which valley polarization is achievable via valley-selective circular dichroism arising from its unique symmetry. We also provide experimental evidence by measuring the circularly polarized photoluminescence on monolayer molybdenum disulphide, which shows up to 50% polarization. The monolayer transition-metal dichalcogenide molybdenum disulphide has recently attracted attention owing to its distinctive electronic properties. Cao and co-workers present numerical evidence suggesting that circularly polarized light can preferentially excite a single valley in the band structure of this system.

Subfields: Electrical and Electronic Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/d09694e36c9d554280c826d767fa20b123478849

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In Electrical and Electronic Engineering

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Citations in the corpus

• Control of two-dimensional excitonic light emission via photonic crystal (2013, background): “Figures 1(a) and (b) show typical devices with light emitting materials (multi-quantum wells) embedded into a 2D PhC, which employs its photonic band-gap [23] and diffraction grating effect [24], to redistribute the emitted photons.”
• Few-layer MoS2: a promising layered semiconductor. (2014, background): “The broken inversion symmetry in monolayer MoS2 also causes valley Hall effect where carriers flow into opposite transverse edges upon application of an in-plane electric field.(53,153,160) The nondegenerate spin energy bands coupled with time reversal symmetry of the”