Electric dipole spin resonance of two-dimensional semiconductor spin qubits

Abstract

Monolayer transition metal dichalcogenides (TMDs) offer a novel two-dimensional platform for semiconductor devices. One such application, whereby the added low dimensional crystal physics (i.e. optical spin selection rules) may prove TMDs a competitive candidate, are quantum dots as qubits. The band structure of TMD monolayers offers a number of different degrees of freedom and combinations thereof as potential qubit bases, primarily electron spin, valley isospin and the combination of the two due to the strong spin-orbit coupling known as a Kramers qubit. Pure spin qubits in monolayer MoX₂ (where X= S or Se) can be achieved by energetically isolating a single valley and tuning to a spin degenerate regime within that valley by a combination of a sufficiently small quantum dot radius and large perpendicular magnetic field. Within such a TMD spin qubit, we theoretically analyse single qubit rotations induced by electric dipole spin resonance. We employ a rotating wave approximation (RWA) within a second order time dependent Schrieffer-Wolf effective Hamiltonian to derive analytic expressions for the Rabi frequency of single qubit oscillations, and optimise the mechanism or the parameters to show oscillations up to \unit[250]MHz. This is significantly faster than similar predictions found for TMD qubits in the Kramers pair spin-valley or valley-only basis as well as experimental results for conventional semiconductor devices.