Spin rotation by resonant electric field in few-level quantum dots: Floquet dynamics and tunneling

Abstract: We study electric dipole spin resonance caused by sub-terahertz (THz) radiation in a multilevel finite-size quantum dot formed in a nanowire focusing on the range of driving electric fields amplitudes where a strong interplay between the Rabi spin oscillations and tunneling from the dot to continuum states can occur. A strong effect of the tunneling on the spin evolution in this regime occurs due to formation of mixed spin states. As a result, the tunneling strongly limits possible spin manipulations time. We demonstrate a backaction of the spin dynamics on the tunneling and position of the electron. The analysis of the efficiency of the spin manipulation in terms of the system energy shows that tunneling decreases this efficiency. Fourier spectra of the time-dependent expectation value of the electron position show a strong effect of the spin-orbit coupling on their low-frequency components. This results can be applied to operational properties of spin-based nanodevices and extending the range of possible spin resonance frequencies to the THz domain.