Two pressure-induced transitions in TiOCl: Mott insulator to anisotropic metal

Yu Zhong Zhang, Harald Olaf Jeschke, Roser Valentí

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)

Abstract

Using Car-Parrinello molecular dynamics we investigate the behavior of the low-dimensional multiorbital Mott insulator TiOCl under pressure. We show that the system undergoes two consecutive phase transitions, first at Pc from a Mott-insulator to a metallic phase in the ab plane with a strong Ti-Ti dimerization along b. At a pressure Pc′>Pc the dimerization disappears and the system behaves as a uniform metal. This second transition has not yet been reported experimentally. We show that the insulator-to-metal transition at Pc is driven by the widening of the bandwidth rather than structural changes or reduction of crystal field splittings and it shows a redistribution of the electronic occupation within the t2g bands. Our computed pressure-dependent lattice parameters are consistent with experimental observations and the existing controversy on the change of crystal symmetry at high pressures is discussed.

Original languageEnglish
Article number136406
JournalPhysical Review Letters
Volume101
Issue number13
DOIs
Publication statusPublished - Sep 25 2008
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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