Electric dipole spin resonance of two-dimensional semiconductor spin qubits

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 a large perpendicular magnetic field. Within such a TMD spin qubit, we theoretically analyze single-qubit rotations induced by electric dipole spin resonance. We employ a rotating-wave approximation within a second-order time-dependent Schrieffer-Wolf effective Hamiltonian to derive analytic expressions for the Rabi frequency of single-qubit oscillations, and optimize the mechanism or the parameters to show oscillations up to 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.