Three-band tight-binding model for monolayers of group-VIB transition metal dichalcogenides

By Gui-Bin Liu, Wen-Yu Shan, Yugui Yao, W. Yao, Di Xiao. 2013

710 citations recorded by the source corpus.

We present a three-band tight-binding (TB) model for describing the low-energy physics in monolayers of group-VIB transition metal dichalcogenides MX2 (M = Mo, W; X = S, Se, Te). As the conduction- and valence-band edges are predominantly contributed by the dz2 , dxy, and dx2 y2 orbitals of M atoms, the TB model is constructed using these three orbitals based on the symmetries of the monolayers. Parameters of the TB model are fitted from the first-principles energy bands for all MX2 monolayers. The TB model involving only the nearest-neighbor M-M hoppings is sufficient to capture the band-edge properties in the K valleys, including the energy dispersions as well as the Berry curvatures. The TB model involving up to the third-nearest-neighbor M-M hoppings can well reproduce the energy bands in the entire Brillouin zone. Spin-orbit coupling in valence bands is well accounted for by including the on-site spin-orbit interactions ofM atoms. The conduction band also exhibits a small valley-dependent spin splitting which has an overall sign difference between MoX2 and WX2. We discuss the origins of these corrections to the three-band model. The three-band TB model developed here is efficient to account for low-energy physics in MX2 monolayers, and its simplicitymore » can be particularly useful in the study of many-body physics and physics of edge states.« less

Subfields: Electrical and Electronic Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/ce6dd1e7a8b50e8c2bec24d5accf803724adac17

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In Electrical and Electronic Engineering

1. Hongyi Yu
2. Xiaodong Xu
3. W. Yao
4. D. Mandrus
5. G. Burkard
6. Q. Niu
7. X. Cui
8. M. Potemski

In Materials Chemistry

1. W. Yao
2. Xiaodong Xu
3. Hongyi Yu
4. Ji Feng
5. Q. Niu
6. X. Cui
7. D. Mandrus
8. Aaron M. Jones

Citations in the corpus

• Spin-orbit coupling, quantum dots, and qubits in monolayer transition metal dichalcogenides (2013, background): “If one neglects the chalcogenide p orbital admixing to the CB, these are the only terms that can explain the spin splitting of the CB, which is found in FP calculations [26,32,36,66,67], and this is the motivation to consider these second-order terms in Ref.”
• Valley excitons in two-dimensional semiconductors (2015, background): “On the other hand SOC slightly renormalizes the effective mass of the two spin-split conduction bands, leading to conduction band crossings in MoX2 but not for WX2 [47] (the upper conduction band at ±K has larger/smaller effective mass than the lower one in MoX2/WX2, see Fig.”
• Optical properties of atomically thin transition metal dichalcogenides: observations and puzzles (2016, background): “ show a considerably smaller SO splitting ( so,cb ). Nevertheless, so,cb remains to be apparent due to the second order effects for d 0 orbitals and an admixture of p-states of chalcogen (X) atoms [32,34,36]. Notably, these two latter effects are expected to yield the opposite in sign contributions”
• Magnetic control of valley pseudospin in monolayer WSe2 (2014, methodology): “en contribute to the Zeeman splitting of valley exciton pseudospin. We consider here the three-band tight-binding (TB) model with either nearest neighbor (NN) or third nearest neighbor (TNN) hoppings [S2], where the TB parameters are obtained by fitting first-principles band structures of relaxed mo”