Slater Insulator in Iridate Perovskites with Strong Spin-Orbit Coupling.
The perovskite SrIrO_{3} is an exotic narrow-band metal owing to a confluence of the strengths of the spin-orbit coupling (SOC) and the electron-electron correlations. It has been proposed that topological and magnetic insulating phases can be achieved by tuning the SOC, Hubbard interactions, and/or lattice symmetry. Here, we report that the substitution of nonmagnetic, isovalent Sn^{4+} for Ir^{4+} in the SrIr_{1-x}Sn_{x}O_{3} perovskites synthesized under high pressure leads to a metal-insulator transition to an antiferromagnetic (AF) phase at T_{N}≥225  K. The continuous change of the cell volume as detected by x-ray diffraction and the λ-shape transition of the specific heat on cooling through T_{N} demonstrate that the metal-insulator transition is of second order. Neutron powder diffraction results indicate that the Sn substitution enlarges an octahedral-site distortion that reduces the SOC relative to the spin-spin exchange interaction and results in the type-G AF spin ordering below T_{N}. Measurement of high-temperature magnetic susceptibility shows the evolution of magnetic coupling in the paramagnetic phase typical of weak itinerant-electron magnetism in the Sn-substituted samples. A reduced structural symmetry in the magnetically ordered phase leads to an electron gap opening at the Brillouin zone boundary below T_{N} in the same way as proposed by Slater.
Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
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Cui
Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.|Materials Science and Engineering Program, University of Texas at Austin, Austin, Texas 78712, USA.
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Cheng
Computational Condensed Matter Physical Laboratory, RIKEN, Wako, Saitama 351-0198, Japan.
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Fan
Quantum Condensed Matter Division, Oak Ridge National Laboratory, Tennessee 37831, USA.
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Taylor
Quantum Condensed Matter Division, Oak Ridge National Laboratory, Tennessee 37831, USA.
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Calder
Materials Science and Technology Division, Oak Ridge National Laboratory, Tennessee 37831, USA.
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McGuire
Materials Science and Technology Division, Oak Ridge National Laboratory, Tennessee 37831, USA.|Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA.
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Yan
Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701, USA.
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Meyers
Materials Science and Engineering Program, University of Texas at Austin, Austin, Texas 78712, USA.
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Li
Materials Science and Engineering Program, University of Texas at Austin, Austin, Texas 78712, USA.
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Cai
Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
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Jiao
Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA.
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Choi
Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA.
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Haskel
Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8581, Japan.
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Gotou
Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8581, Japan.
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Uwatoko
Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, USA.
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Chakhalian
Quantum Condensed Matter Division, Oak Ridge National Laboratory, Tennessee 37831, USA.|Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA.
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Christianson
Computational Condensed Matter Physical Laboratory, RIKEN, Wako, Saitama 351-0198, Japan.|Computational Materials Science Research Team, RIKEN Advanced Institute for Computational Science (AICS), Kobe, Hyogo 650-0047, Japan.|Computational Quantum Matter Research Team, RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan.
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Yunoki
Materials Science and Engineering Program, University of Texas at Austin, Austin, Texas 78712, USA.
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Goodenough
Materials Science and Engineering Program, University of Texas at Austin, Austin, Texas 78712, USA.
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Zhou