Ultrafast electron dynamics in monolayer MoS₂interacting with optical pulse influenced by exchange field and waveform

In this paper, we investigate the effect of waveform and carrier-envelope phase on the electron dynamics in monolayer MoS₂interacting with an ultrashort (few-femtosecond) optical pulse in the presence of magnetic exchange field. The waveform of the zero area pulse is characterized by Hermite-Gaussian polynomials associated with time-dependent and carrier-envelope phases. Because the duration of optical pulse is less than the characteristic electron scattering time (10-100 fs), the electron dynamics is coherent, and can be described by the time-dependent Schrödinger equation. We show, that the electron transition from valence band to conduction band is a deeply irreversible dynamics, which implies quantum electron dynamics is highly nonadiabatic. We study the effect of carrier-envelope phase and exchange field on the conduction band population for two types of waveform. Electron distribution in reciprocal space gives asymmetric hot spots in differentKandK' valleys after the pulse ends (valley polarization effect), which is found to be more sensitive to carrier-envelope phase. The predicted effect provides new opportunities for the improvement of information processing in the petahertz domain and optoelectronics applications.