Simultaneous Metal-Insulator and Antiferromagnetic Transitions in Orthorhombic Perovskite Iridate Sr_0.94Ir_0.78O_2.68 Single Crystals

Authors

Hao Zheng, University of KentuckyFollow
Jsaminka Terzic, University of KentuckyFollow
Feng Ye, University of Kentucky
X. G. Wan, Nanjing University, China
D. Wang, Nanjing University, China
Jinchen Wang, University of KentuckyFollow
Xiaoping Wang, Oak Ridge National Laboratory
P. Schlottmann, Florida State University
Shujuan Yuan, University of KentuckyFollow
Gang Cao, University of KentuckyFollow

Abstract

The orthorhombic perovskite SrIrO₃ is a semimetal, an intriguing exception in iridates where the strong spin-orbit interaction coupled with electron correlations tends to impose an insulating state. We report results of our investigation of bulk single-crystal S_r0.94Ir_0.78O_2.68 or Ir-deficient, orthorhombic perovskite SrIrO₃. It retains the same crystal structure as stoichiometric SrIrO₃ but exhibits a sharp, simultaneous antiferromagnetic (AFM) and metal-insulator (MI) transition occurring in the basal-plane resistivity at 185 K. Above it, the basal-plane resistivity features an extended regime of almost linear temperature dependence up to 800 K but the strong electronic anisotropy renders an insulating behavior in the out-of-plane resistivity. The Hall resistivity undergoes an abrupt sign change and grows below 40 K, which along with the Sommerfeld constant of 20mJ/molK² suggests a multiband effect. All results including our first-principles calculations underscore a delicacy of the paramagnetic, metallic state in SrIrO₃ that is in close proximity to an AFM insulating state. The contrasting ground states in isostructural Sr_0.94Ir_0.78O_2.68 and SrIrO₃ illustrate a critical role of lattice distortions and Ir deficiency in rebalancing the ground state in the iridates. Finally, the concurrent AFM and MI transitions reveal a direct correlation between the magnetic transition and formation of an activation gap in the iridate, which is conspicuously absent in Sr2IrO₄.

Document Type

Article

Publication Date

6-27-2016

Notes/Citation Information

Published in Physical Review B, v. 93, issue 23, 235157, p. 1-7.

©2016 American Physical Society

The copyright holder has granted permission for posting the article here.

Digital Object Identifier (DOI)

https://doi.org/10.1103/PhysRevB.93.235157

Funding Information

This work was supported by NSF through Grant No. DMR-1265162 and the Department of Energy (BES) through Grant No. DE-FG02-98ER45707 (P.S.). X.G.W. acknowledges support by Natural Science Foundation of China via Grant No.11525417.

Repository Citation

Zheng, Hao; Terzic, Jsaminka; Ye, Feng; Wan, X. G.; Wang, D.; Wang, Jinchen; Wang, Xiaoping; Schlottmann, P.; Yuan, Shujuan; and Cao, Gang, "Simultaneous Metal-Insulator and Antiferromagnetic Transitions in Orthorhombic Perovskite Iridate Sr_0.94Ir_0.78O_2.68 Single Crystals" (2016). Center for Advanced Materials Faculty Publications. 9.
https://uknowledge.uky.edu/cam_facpub/9