Holstein polaron in a valley-degenerate two-dimensional semiconductor
Two-dimensional (2D) crystals have emerged as a class of materials with tunable carrier density . Carrier doping to 2D semiconductors can be used to modulate many-body interactions and to explore novel composite particles. The Holstein polaron is a small composite particle of an electron that carrie...
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Published in | Nature materials Vol. 17; no. 8; pp. 676 - 680 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
England
Nature Publishing Group
01.08.2018
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Subjects | |
Online Access | Get full text |
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Summary: | Two-dimensional (2D) crystals have emerged as a class of materials with tunable carrier density
. Carrier doping to 2D semiconductors can be used to modulate many-body interactions
and to explore novel composite particles. The Holstein polaron is a small composite particle of an electron that carries a cloud of self-induced lattice deformation (or phonons)
, which has been proposed to play a key role in high-temperature superconductivity
and carrier mobility in devices
. Here we report the discovery of Holstein polarons in a surface-doped layered semiconductor, MoS
, in which a puzzling 2D superconducting dome with the critical temperature of 12 K was found recently
. Using a high-resolution band mapping of charge carriers, we found strong band renormalizations collectively identified as a hitherto unobserved spectral function of Holstein polarons
. The short-range nature of electron-phonon (e-ph) coupling in MoS
can be explained by its valley degeneracy, which enables strong intervalley coupling mediated by acoustic phonons. The coupling strength is found to increase gradually along the superconducting dome up to the intermediate regime, which suggests a bipolaronic pairing in the 2D superconductivity. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1476-1122 1476-4660 |
DOI: | 10.1038/s41563-018-0092-7 |