Intervalley coupling by quantum dot confinement potentials in monolayer transition metal dichalcogenides

Abstract

Monolayer transition metal dichalcogenides (TMDs) offer new opportunities for realizing quantum dots (QDs) in the ultimate two-dimensional (2D) limit. Given the rich control possibilities of electron valley pseudospin discovered in the monolayers, this quantum degree of freedom can be a promising carrier of information for potential quantum spintronics exploiting single electrons in TMD QDs. An outstanding issue is to identify the degree of valley hybridization, due to the QD confinement, which may significantly change the valley physics in QDs from its form in the 2D bulk. Here we perform a systematic study of the intervalley coupling by QD confinement potentials on extended TMD monolayers. We find that the intervalley coupling in such geometry is generically weak due to the vanishing amplitude of the electron wavefunction at the QD boundary, and hence valley hybridization shall be well quenched by the much stronger spin-valley coupling in monolayer TMDs and the QDs can well inherit the valley physics of the 2D bulk. We also discover sensitive dependence of intervalley coupling strength on the central position and the lateral length scales of the confinement potentials, which may possibly allow tuning of intervalley coupling by external controls

17 pages, 14 figures

References in corpus (15)

• The electronic properties of graphene
• Valley polarization in MoS2 monolayers by optical pumping
• Chaotic Dirac billiard in graphene quantum dots
• Valley Dependent Optoelectronics from Inversion Symmetry Breaking
• Strong interlayer coupling in van der Waals heterostructures built from single-layer chalcogenides
• Spin qubits in graphene quantum dots
• Vapor-Solid Growth of High Optical Quality MoS2 Monolayers With Near-Unity Valley Polarization
• Bound states and magnetic field-induced valley splitting in gate-tunable graphene quantum dots
• Quasi-bound states of quantum dots in single and bilayer graphene
• Electron-Hole Crossover in Graphene Quantum Dots
• The Fock-Darwin States of Dirac Electrons in Graphene-based Artificial Atoms
• Quantum computing by optical control of electron spins
• Physical mechanisms of interface-mediated intervalley coupling in Si
• Spin and valley-orbit splittings in SiGe/Si heterostructures
• Incompatibility of modulated checkerboard patterns with the neutron scattering resonance peak in cuprate superconductors

Cited by in corpus (4)

• k.p theory for two-dimensional transition metal dichalcogenide semiconductors
• Electrical Control of Second-Harmonic Generation in a WSe2 Monolayer Transistor
• Two-Dimensional Valley Electrons and Excitons in Noncentrosymmetric 3R MoS${}_2$
• Optically Active Quantum Dots in Monolayer WSe${}_2$