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arXiv · 1303.5551

Electronic Instability in a Zero-Gap Semiconductor: the Charge-Density Wave in (TaSe4)2I

C. Tournier-Colletta·L. Moreschini·G. Autès·S. Moser·A. Crepaldi·H. Berger·A. L. Walter·K. S. Kim·A. Bostwick·P. Monceau·E. Rotenberg·O. V. Yazyev·M. Grioni
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Abstract

We report a comprehensive study of the paradigmatic quasi-1D compound (TaSe4)2I performed by means of angle-resolved photoemission spectroscopy (ARPES) and first-principles electronic structure calculations. We find it to be a zero-gap semiconductor in the non-distorted structure, with non-negligible interchain coupling. Theory and experiment support a Peierls-like scenario for the CDW formation below T_CDW = 263 K, where the incommensurability is a direct consequence of the finite interchain coupling. The formation of small polarons, strongly suggested by the ARPES data, explains the puzzling semiconductor-to-semiconductor transition observed in transport at T_CDW.

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C. Tournier-Colletta, L. Moreschini, G. Autès, S. Moser, A. Crepaldi, H. Berger, A. L. Walter, K. S. Kim, A. Bostwick, P. Monceau, E. Rotenberg, O. V. Yazyev, M. Grioni. 2013-03-22. Electronic Instability in a Zero-Gap Semiconductor: the Charge-Density Wave in (TaSe4)2I. https://doi.org/10.1103/physrevlett.110.236401

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