Spin-orbit tuned metal-insulator transitions in single-crystal Sr2Ir1-xRhxO4 (0\leqx\leq1)

Abstract

Sr2IrO4 is a magnetic insulator driven by spin-orbit interaction (SOI) whereas the isoelectronic and isostructural Sr2RhO4 is a paramagnetic metal. The contrasting ground states have been shown to result from the critical role of the strong SOI in the iridate. Our investigation of structural, transport, magnetic and thermal properties reveals that substituting 4d Rh4+ (4d5) ions for 5d Ir4+(5d5) ions in Sr2IrO4 directly reduces the SOI and rebalances the competing energies so profoundly that it generates a rich phase diagram for Sr2Ir1-xRhxO4 featuring two major effects: (1) Light Rh doping (0\leqx\leq0.16) prompts a simultaneous and precipitous drop in both the electrical resistivity and the magnetic ordering temperature TC, which is suppressed to zero at x = 0.16 from 240 K at x=0. (2) However, with heavier Rh doping (0.24< x<0.85 (\pm0.05)) disorder scattering leads to localized states and a return to an insulating state with spin frustration and exotic magnetic behavior that only disappears near x=1. The intricacy of Sr2Ir1-xRhxO4 is further highlighted by comparison with Sr2Ir1-xRuxO4 where Ru4+(4d4) drives a direct crossover from the insulating to metallic states.

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References in corpus (7)

• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
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• Twisted Hubbard Model for Sr2IrO4: Magnetism and Possible High Temperature Superconductivity
• Strong spin-orbit coupling effects on the Fermi surface of Sr2RuO4 and Sr2RhO4
• Microscopic study of spin-orbit-induced Mott insulator in Ir oxides
• Coulomb-Enhanced Spin-Orbit Splitting: The Missing Piece in the Sr2RhO4 Puzzle
• Electronic structures of layered perovskite Sr2MO4 (M=Ru, Rh, and Ir)

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• Dual gate control of bulk transport and magnetism in the spin-orbit insulator Sr2IrO4
• Charge partitioning and anomalous hole doping in Rh-doped Sr2IrO4
• Lattice frustration in spin-orbit Mott insulator Sr3Ir2O7 at high pressure
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• Tuning the electronic structure of Sr2IrO4 thin films by bulk electronic doping using molecular beam epitaxy
• Calculating branching ratio and spin-orbit coupling from first-principles: A formalism and its application to iridates
• Crystal structure and physical properties of the Sr-vacant spin-orbit-coupling induced Mott insulator Sr2-xIrO4
• Doping driven structural distortion in the bilayer iridate (Sr${}_{1-x}$La${}_x$)${}_3$Ir${}_2$O${}_7$
• Hallmarks of the Mott-Metal Crossover in the Hole Doped J=1/2 Mott insulator Sr2IrO4