Effect of valley, spin, and band nesting on the electronic properties of gated quantum dots in a single layer of transition metal dichalcogenides

Abstract

We present here results of atomistic theory of electrons confined by metallic gates in a single layer of transition metal dichalcogenides. The electronic states are described by the tight-binding model and computed using a computational box including up to million atoms with periodic boundary conditions and parabolic confining potential due to external gates embedded in it. With this methodology applied to MoS2, we find a twofold degenerate energy spectrum of electrons confined in the two non-equivalent K-valleys by the metallic gates as well as six-fold degenerate spectrum associated with Q-valleys. We compare the electron spectrum with the energy levels of electrons confined in GaAs/GaAlAs and in self-assembled quantum dots. We discuss the role of spin splitting and topological moments on the K and Q valley electronic states in quantum dots with sizes comparable to experiment. arXiv:1907.09512v1 [cond-mat.mes-hall]

Electronic Properties of Bulk and Single-Layer MoS2 Using ab Initio DFT: Application of Spin-Orbit Coupling (SOC) Parameters

“…2(a-d), the valence band maximum (VBM) and the conduction band minimum (CBM) lie below and above the Femi level respectively along with the K-symmetry. For the monolayer MoS 2 , there is a reasonable band splitting as seen in Fig 2 (c) and (d), this band splitting is brought about by the utilization of SOC and can likewise help in the application of spintronic and valleytronics [43][44][45][46][47]. The band splitting is observed distinctly in the valence band (VB) of the high symmetry K-direction.…”

Spatial Selected Spin Filtering Effect in Z-Shaped MoS2 Nanoribbon

“…The principle of spin polarization in this work is quite different from Ref. [12][13][14][24][25][26]. As the fully spin polarization are detected in several energy regions, thus this structure has potential applications in making spintronic device.…”

“…As we mentioned in above discussion, the electric field is essential in Ref. [12][13][14][24][25][26] to achieve the spin polarization. Without electric field, the spin polarization in uniform MoS2-ZR is weak [25,26].…”

“…Spin and valley index dependent phenomena indicate that MoS2 is a promising material for making spintronic devices, and what is more, different approaches are taken to explore the spin polarization effect in MoS2 [9][10][11]. Gated MoS2 quantum dots were used to obtain spin and valley polarized states [12][13][14]. By measuring the susceptibility at optical frequencies, the spin polarized ground state was experimentally probed by J. G. Roch, et al [15].…”

Spin-valley qubits in gated quantum dots in a single layer of transition metal dichalcogenides

“…By working in reciprocal space, the valleys were explicitly taken into account. The effect of valley, spin, and band nesting on the electronic properties of gated quantum dots in a single layer of transition metal dichalcogenides was described [73], along with valley-and spin-polarized brokensymmetry many-body states discussed in Ref. 74.…”