Coherent Spin Dynamics of Localized Electrons in Monolayer MoS₂

Abstract

Compared with itinerant electrons in monolayer transition-metal dichalcogenides, localized electrons exhibit coherent spin precession in transverse magnetic fields B and usually have longer spin relaxation times. Here, we uncover the intrinsic spin dephasing processes of localized electrons whose mechanism remains unclear. Electron spin coherence dynamics are studied by time-resolved Faraday rotation spectroscopy in monolayer MoS 2 , where four subensembles of localized electrons are found with different g factor values and inhomogeneous broadening. The spin dephasing rates of all four subensembles include a linearly B-dependent part due to g-factor inhomogeneity and a B-independent part dominated by electron−nuclear hyperfine interaction and/or anisotropic exchange interaction. The hyperfine-induced spin dephasing time is ∼30−40 ns, and the anisotropic exchange-induced spin dephasing time is on the order of subnanoseconds. The findings give insight into the coherent spin dynamics of localized electrons in monolayers and the interaction between the electron spin and its environment.

Study of Spin Localization and Charge Transport in Hydrothermally Synthesized 2H-MoS2

“…There are several other EPR measurements in the literature, where the sulfur vacancy and sulfur antisite are the most reported paramagnetic defects in MoS 2 . ,, Besides identifying the nature of the defect, EPR spectroscopy also offers the measurement of spin dephasing time. In the literature, there are few reports of spin dephasing time measurements optically in the range of 30–50 ns, , which can be further tuned by material engineering.…”

“…17,22,23 Besides identifying the nature of the defect, EPR spectroscopy also offers the measurement of spin dephasing time. In the literature, there are few reports of spin dephasing time measurements optically in the range of 30−50 ns, 24,25 which can be further tuned by material engineering.…”