Electron–phonon coupling in single-layer MoS₂

The electron–phonon coupling strength in the spin–split valence band maximum of single-layer MoS₂ is studied using angle-resolved photoemission spectroscopy and density functional theory-based calculations. Values of the electron–phonon coupling parameter λ are obtained by measuring the linewidth of the spin–split bands as a function of temperature and fitting the data points using a Debye model. The experimental values of λ for the upper and lower spin–split bands at K are found to be 0.05 and 0.32, respectively, in excellent agreement with the calculated values for a free-standing single-layer MoS₂. The results are discussed in the context of spin and phase-space restricted scattering channels, as reported earlier for single-layer WS₂ on Au(111). The fact that the absolute valence band maximum in single-layer MoS₂ at K is almost degenerate with the local valence band maximum at Γ can potentially be used to tune the strength of the electron–phonon interaction in this material.