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arXiv · 0706.4455

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

G. Li·W. Z. Hu·J. Dong·D. Qian·D. Hsieh·M. Z. Hasan·E. Morosan·R. J. Cava·N. L. Wang
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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.

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G. Li, W. Z. Hu, J. Dong, D. Qian, D. Hsieh, M. Z. Hasan, E. Morosan, R. J. Cava, N. L. Wang. 2007-06-29. Anomalous metallic state of Cu$_{0.07}$TiSe$_2$: an optical spectroscopy study. https://doi.org/10.1103/physrevlett.99.167002

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