Anomalous metallic state of Cu${}_{0.07}$TiSe${}_2$: an optical spectroscopy study

Abstract

We report an optical spectroscopy study on the newly discovered superconductor Cu${}_{0.07}$TiSe${}_2$. Consistent with the development from a semimetal or semiconductor with a very small indirect energy gap upon doping TiSe${}_2$, it is found that the compound has a low carrier density. Most remarkably, the study reveals a substantial shift of the "screened" plasma edge in reflectance towards high energy with decreasing temperature. This phenomenon, rarely seen in metals, indicates either a sizeable increase of the conducting carrier concentration or/and a decrease of the effective mass of carriers with reducing temperature. We attribute the shift primarily to the later effect.

arXiv comment4 figures, 4+ pages

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• Superconductivity in Cu_xTiSe_2
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Cited by in corpus (3)

• Coexistence of bulk superconductivity and charge density wave in CuxZrTe3
• Effect of Cu intercalation and pressure on excitonic interaction in 1T-TiSe2
• Optical signatures of type-II Weyl fermions in the noncentrosymmetric semimetals $R$AlSi ($R$=La, Ce, Pr, Nd, Sm)