Ultrafast electron spin dynamics in bulk CdTe investigated by femtosecond pump-probe reflection spectroscopy

Abstract

The transient spin polarization dynamics in bulk cadmium telluride (CdTe) at 70 K is investigated by the circularly polarized pump-probe reflection technique. A general expression is derived from the rate equations of a two-level system with small signal approximation to describe the light-helicity-dependent reflection spectrum. The initial degree of electron spin polarization in the excited state and the electron spin relaxation time in bulk CdTe at low temperature with different carrier density are analyzed according to this model. Our experimental results reveal that the Dʼyakonov–Perelʼ mechanism based on a fully microscopic kinetic spin Bloch equation (microscopic KSBE) approach dominates in the electron spin relaxation process in bulk CdTe crystal. • The transient spin polarization dynamics in bulk CdTe at 70 K is investigated. • A general expression is derived from the rate equations of a two-level system. • P s 0 and τ s in bulk CdTe are analyzed according to this model. • The DP mechanism based on KSBE dominates the electron spin relaxation process.