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arXiv · 1706.05484

Electron-phonon coupling in the spin-split valence band of single layer WS$_2$

Nicki Frank Hinsche·Arlette S. Ngankeu·Kevin Guilloy·Sanjoy K. Mahatha·Antonija Grubišić Čabo·Marco Bianchi·Maciej Dendzik·Charlotte E. Sanders·Jill A. Miwa·Harsh Bana·Elisabetta Travaglia·Paolo Lacovig·Luca Bignardi·Rosanna Larciprete·Alessandro Baraldi·Silvano Lizzit·Kristian Sommer Thygesen·Philip Hofmann
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Abstract

The absence of inversion symmetry leads to a strong spin-orbit splitting of the upper valence band of semiconducting single layer transition metal dichalchogenides such as MoS$_2$ or WS$_2$. This permits a direct comparison of the electron-phonon coupling strength in states that only differ by their spin. Here, the electron-phonon coupling in the valence band maximum of single-layer WS$_2$ is studied by first principles calculations and angle-resolved photoemission. The coupling strength is found to be drastically different for the two spin-split branches, with calculated values of $\lambda_K=$0.0021 and 0.40 for the upper and lower spin-split valence band of the free-standing layer, respectively. This difference is somewhat reduced when including scattering processes involving the Au(111) substrate present in the experiment and the experimental results confirm the strongly branch-dependent coupling strength.

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Nicki Frank Hinsche, Arlette S. Ngankeu, Kevin Guilloy, Sanjoy K. Mahatha, Antonija Grubišić Čabo, Marco Bianchi, Maciej Dendzik, Charlotte E. Sanders, Jill A. Miwa, Harsh Bana, Elisabetta Travaglia, Paolo Lacovig, Luca Bignardi, Rosanna Larciprete, Alessandro Baraldi, Silvano Lizzit, Kristian Sommer Thygesen, Philip Hofmann. 2017-06-17. Electron-phonon coupling in the spin-split valence band of single layer WS$_2$. https://doi.org/10.1103/physrevb.96.121402

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