A Unique Crystal Structure of Ca₂RuO₄ in the Current Stabilized Semi-Metallic State

2018/06/30 by J. Bertinshaw, N. Gurung, P. Jorba +13 · 1 citation
Physics and Astronomy · #cond-mat.str-el

paper · pdf · doi:10.1103/physrevlett.123.137204

published as Phys. Rev. Lett. 123, 137204 (2019) · 12 pages, 3 figures, 1 table

arxiv created 2019/05/21 · arxiv updated 2019/10/02

Abstract

The electric-current stabilized semi-metallic state in the quasi-two-dimensional Mott insulator Ca₂RuO₄ exhibits an exceptionally strong diamagnetism. Through a comprehensive study using neutron and X-ray diffraction, we show that this non-equilibrium phase assumes a crystal structure distinct from those of equilibrium metallic phases realized in the ruthenates by chemical doping, high pressure and epitaxial strain, which in turn leads to a distinct electronic band structure. Dynamical mean field theory calculations based on the crystallographically refined atomic coordinates and realistic Coulomb repulsion parameters indicate a semi-metallic state with partially gapped Fermi surface. Our neutron diffraction data show that the non-equilibrium behavior is homogeneous, with antiferromagnetic long-range order completely suppressed. These results provide a new basis for theoretical work on the origin of the unusual non-equilibrium diamagnetism in Ca₂RuO₄.

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