Temperature-dependent localized excitations of doped carriers in superconducting diamond.
Laser-excited photoemission spectroscopy is used to show that the doped carriers in metallic or superconducting diamond couple strongly to the lattice via high-energy (approximately 150 meV) optical phonons, with direct observations of localized Franck-Condon multiphonon sidebands appearing as Fermi-edge replicas. It exhibits a temperature-dependent spectral weight transfer from higher to lower energy sidebands and zero-phonon Fermi-edge states. The quantified coupling strength shows a systematic increase on lowering temperature, implicating its relation to the normal state transport and superconductivity.
Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan.
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Ishizaka
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R
Eguchi
S
S
Tsuda
A
A
Chainani
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T
Yokoya
T
T
Kiss
T
T
Shimojima
T
T
Togashi
S
S
Watanabe
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Chen
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Y
Takano
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M
Nagao
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I
Sakaguchi
T
T
Takenouchi
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H
Kawarada
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Shin