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arXiv · 1806.06455

A Unique Crystal Structure of Ca$_2$RuO$_4$ in the Current Stabilized Semi-Metallic State

J. Bertinshaw·N. Gurung·P. Jorba·H. Liu·M. Schmid·D. T. Mantadakis·M. Daghofer·M. Krautloher·A. Jain·G. H. Ryu·O. Fabelo·P. Hansmann·G. Khaliullin·C. Pfleiderer·B. Keimer·B. J. Kim
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Abstract

The electric-current stabilized semi-metallic state in the quasi-two-dimensional Mott insulator Ca$_2$RuO$_4$ 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 Ca$_2$RuO$_4$.

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J. Bertinshaw, N. Gurung, P. Jorba, H. Liu, M. Schmid, D. T. Mantadakis, M. Daghofer, M. Krautloher, A. Jain, G. H. Ryu, O. Fabelo, P. Hansmann, G. Khaliullin, C. Pfleiderer, B. Keimer, B. J. Kim. 2018-06-17. A Unique Crystal Structure of Ca$_2$RuO$_4$ in the Current Stabilized Semi-Metallic State. https://doi.org/10.1103/physrevlett.123.137204

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