Spin-Degenerate Regimes for Single Quantum Dots in Transition Metal Dichalcogenide Monolayers

Abstract

Strong spin-orbit coupling in transition metal dichalcogenide (TMDC) monolayers results in spin resolvable band structures about the $K$ and $K^{\prime }$ valleys such that the eigenbasis of a 2D quantum dot (QD) in a TMDC monolayer in zero field is described by the Kramers pairs $|0{⟩}_{-}=|K^{\prime }\uparrow ⟩$, $|1{⟩}_{-}=|K\downarrow ⟩$ and $|0{⟩}_{+}=|K\uparrow ⟩$, $|1{⟩}_{+}=|K^{\prime }\downarrow ⟩$. The strong spin-orbit coupling limits the usefulness of single TMDC QDs as spin qubits. Possible regimes of spin-degenerate states, overcoming the spin-orbit coupling in monolayer TMDC QDs are investigated in both zero field, where the spin and valley degrees of freedom become fourfold degenerate, and twofold degeneracy in some magnetic field, localised to a given valley. Such regimes are shown to be achievable in MoS${}_2$, where the spin orbit coupling is sufficiently low and of the right sign such that the spin resolved conduction bands intersect at points about the $K$ and $K^{\prime }$ valleys and as such may be exploited by selecting suitable critical dot radii.

7 pages, 6 figures, v2: minor corrections

References in corpus (12)

• Valley polarization in MoS2 monolayers by optical pumping
• Substrate-induced band gap opening in epitaxial graphene
• k.p theory for two-dimensional transition metal dichalcogenide semiconductors
• Magnetic Control of Valley Pseudospin in Monolayer WSe2
• Valley Zeeman Effect in Elementary Optical Excitations of a Monolayer WSe2
• Robust optical emission polarization in MoS2 monolayers through selective valley excitation
• Ultrafast Manipulation of Valley Pseudospin
• Intervalley Scattering and Localization Behaviors of Spin-Valley Coupled Dirac Fermions
• Bound states and magnetic field-induced valley splitting in gate-tunable graphene quantum dots
• Bends In Nanotubes Allow Electric Spin Control and Coupling
• Valley Zeeman effect and spin-valley polarized conductance in monolayer MoS${}_2$ in a perpendicular magnetic field
• Intervalley coupling by quantum dot confinement potentials in monolayer transition metal dichalcogenides

Cited by in corpus (12)

• Gate-Tunable Quantum Dot in a High Quality Single Layer MoS${}_2$ Van der Waals Heterostructure
• Dielectrics for Two-Dimensional Transition Metal Dichalcogenide Applications
• Impurity-assisted electric control of spin-valley qubits in monolayer MoS${}_2$
• Theory of Strain-Induced Confinement in Transition Metal Dichalcogenide Monolayers
• Gate-defined, Accumulation-mode Quantum Dots in Monolayer and Bilayer WSe${}_2$
• Valley two-qubit system in a MoS${}_2$-monolayer gated double quantum dot
• The effect of valley, spin and band nesting on the electronic properties of gated quantum dots in a single layer of transition metal dichalcogenides (TMDCs)
• Electric Dipole Spin Resonance of 2D Semiconductor Spin Qubits
• Spin switching via quantum dot spin valves
• Geometric band properties in strained monolayer transition metal dichalcogenides using simple band structures
• Spin-valley qubits in gated quantum dots in a single layer of transition metal dichalcogenides
• Hyperfine Interaction in a MoS${}_2$ Quantum Dot: Decoherence of a Spin-Valley Qubit