Lattice distortions and the metal-insulator transition in pure and Ti-substituted Ca3Ru2O7

V Petkov; T Durga Rao; A Zafar; A M Milinda Abeykoon; E Fletcher; J Peng; Z Q Mao; X Ke

doi:10.1088/1361-648X/ac9dda

Lattice distortions and the metal-insulator transition in pure and Ti-substituted Ca₃Ru₂O₇

J Phys Condens Matter. 2022 Nov 8;51(1). doi: 10.1088/1361-648X/ac9dda.

Authors

V Petkov¹, T Durga Rao^{1

2}, A Zafar¹, A M Milinda Abeykoon³, E Fletcher⁴, J Peng⁵, Z Q Mao⁶, X Ke⁴

Affiliations

¹ Department of Physics, Central Michigan University, Mt. Pleasant, MI 48858, United States of America.
² Department of Physics, GITAM, Visakhapatnam, Andhra Pradesh 530045, India.
³ Photon Sciences Division, Brookhaven National Laboratory, Upton, NY 11973, United States of America.
⁴ Department Physics and Astronomy, Michigan State University, East Lansing, MI 48824, United States of America.
⁵ School of Physics, Southeast University, Nanjin, People's Republic of China.
⁶ Department of Physics, Pennsylvania State University, University Park, State College, PA 16802, United States of America.

PMID: 36301709
DOI: 10.1088/1361-648X/ac9dda

Abstract

We report pair distribution function studies on the relationship between the metal-insulator transition (MIT) and lattice distortions in pure and Ti-substituted bilayer Ca₃Ru₂O₇. Structural refinements performed as a function of temperature, magnetic field and length scale reveal the presence of lattice distortions not only within but also orthogonal to the bilayers. Because of the distortions, the local and average crystal structure differ across a broad temperature region extending from room temperature to temperatures below the MIT. The coexistence of distinct lattice distortions is likely to be behind the marked structural flexibility of Ca₃Ru₂O₇under external stimuli. This observation highlights the ubiquity of lattice distortions in an archetypal Mott system and calls for similar studies on other families of strongly correlated materials.

Keywords: distortions; lattice; metal–insulator transition; strongly correlated systems.