Pressure-induced coherent sliding-layer transition in the excitonic insulator Ta2NiSe5.

ABSTRACT: The crystal structure of the excitonic insulator Ta2NiSe5 has been investigated under a range of pressures, as determined by the complementary analysis of both single-crystal and powder synchrotron X-ray diffraction measurements. The monoclinic ambient-pressure excitonic insulator phase II transforms upon warming or under a modest pressure to give the semiconducting C-centred orthorhombic phase I. At higher pressures (i.e. >3 GPa), transformation to the primitive orthorhombic semimetal phase III occurs. This transformation from phase I to phase III is a pressure-induced first-order phase transition, which takes place through coherent sliding between weakly coupled layers. This structural phase transition is significantly influenced by Coulombic interactions in the geometric arrangement bet

SUBMITTER: Nakano A 

PROVIDER: S-EPMC5947720 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature