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Full-Text Articles in Physics
Electronic And Optical Properties Of La-Doped Sr3Ir2O7 Epitaxial Thin Films, Maryam Souri, Jsaminka Terzic, J. M. Johnson, John G. Connell, John H. Gruenewald, J. Thompson, Joseph W. Brill, J. Hwang, Gang Cao, Sung S. Ambrose Seo
Electronic And Optical Properties Of La-Doped Sr3Ir2O7 Epitaxial Thin Films, Maryam Souri, Jsaminka Terzic, J. M. Johnson, John G. Connell, John H. Gruenewald, J. Thompson, Joseph W. Brill, J. Hwang, Gang Cao, Sung S. Ambrose Seo
Physics and Astronomy Faculty Publications
We have investigated structural, transport, and optical properties of tensile strained (Sr1−xLax)3Ir2O7 (x = 0, 0.025, 0.05) epitaxial thin films. While high-Tc superconductivity is predicted theoretically in the system, we have observed that all of the samples remain insulating with finite optical gap energies and Mott variable-range hopping characteristics in transport. Cross-sectional scanning transmission electron microscopy indicates that structural defects such as stacking faults appear in this system. The insulating behavior of the La-doped Sr3Ir2O7 thin films is presumably due to disorder-induced …
Evidence For A Low-Temperature Magnetic Ground State In Double-Perovskite Iridates With Ir5+(5D4) Ions, Jasminka Terzic, H. Zheng, Feng Ye, H. D. Zhao, P. Schlottmann, Lance E. De Long, S. J. Yuan, Gang Cao
Evidence For A Low-Temperature Magnetic Ground State In Double-Perovskite Iridates With Ir5+(5D4) Ions, Jasminka Terzic, H. Zheng, Feng Ye, H. D. Zhao, P. Schlottmann, Lance E. De Long, S. J. Yuan, Gang Cao
Physics and Astronomy Faculty Publications
We report an unusual magnetic ground state in single-crystal, double-perovskite Ba2YIrO6 and Sr-doped Ba2YIrO6 with Ir5+(5d4) ions. Long-range magnetic order below 1.7 K is confirmed by dc magnetization, ac magnetic susceptibility, and heat-capacity measurements. The observed magnetic order is extraordinarily delicate and cannot be explained in terms of either a low-spin S = 1 state, or a singlet Jeff = 0 state imposed by the spin-orbit interactions (SOI). Alternatively, the magnetic ground state appears consistent with a SOI that competes with comparable Hund's rule coupling and inherently large …
Suppression Of Magnetism In Ba5Alir2O11: Interplay Of Hund's Coupling, Molecular Orbitals, And Spin-Orbit Interaction, Sergey V. Streltsov, Gang Cao, Daniel I. Khomskii
Suppression Of Magnetism In Ba5Alir2O11: Interplay Of Hund's Coupling, Molecular Orbitals, And Spin-Orbit Interaction, Sergey V. Streltsov, Gang Cao, Daniel I. Khomskii
Center for Advanced Materials Faculty Publications
The electronic and magnetic properties of Ba5AlIr2O11 containing Ir-Ir dimers are investigated using the generalized gradient approximation (GGA) and GGA + spin-orbit coupling (SOC) calculations. We found that the strong suppression of the magnetic moment in this compound recently found by Terzic et al. [Phys. Rev. B 91, 235147 (2015)] is not due to charge ordering but is related to the joint effect of the spin-orbit interaction and strong covalency, resulting in the formation of metal-metal bonds. They conspire and act against the intraatomic Hund's rule exchange interaction to reduce total magnetic moment of the …
Optical Signatures Of Spin-Orbit Exciton In Bandwidth-Controlled Sr2Iro4 Epitaxial Films Via High-Concentration Ca And Ba Doping, Maryam Souri, B. H. Kim, John H. Gruenewald, John G. Connell, J. Thompson, J. Nichols, Jsaminka Terzic, B. I. Min, Gang Cao, Joseph W. Brill, Sung S. Ambrose Seo
Optical Signatures Of Spin-Orbit Exciton In Bandwidth-Controlled Sr2Iro4 Epitaxial Films Via High-Concentration Ca And Ba Doping, Maryam Souri, B. H. Kim, John H. Gruenewald, John G. Connell, J. Thompson, J. Nichols, Jsaminka Terzic, B. I. Min, Gang Cao, Joseph W. Brill, Sung S. Ambrose Seo
Physics and Astronomy Faculty Publications
We have investigated the electronic and optical properties of (Sr1−xCax)2IrO4 (x = 0–0.375) and (Sr1−yBay)2IrO4 (y = 0–0.375) epitaxial thin films, in which the bandwidth is systematically tuned via chemical substitutions of Sr ions by Ca and Ba. Transport measurements indicate that the thin-film series exhibits insulating behavior, similar to the Jeff = 1/2 spin-orbit Mott insulator Sr2IrO4. As the average A-site ionic radius increases from (Sr1−xCax)2IrO4 to (Sr …
Doping Evolution Of Magnetic Order And Magnetic Excitations In (Sr1-XLaX)3Ir2O7, Xingye Lu, D. E. Mcnally, M. Moretti Sala, Jsaminka Terzic, M. H. Upton, D. Casa, G. Ingold, Gang Cao, T. Schmitt
Doping Evolution Of Magnetic Order And Magnetic Excitations In (Sr1-XLaX)3Ir2O7, Xingye Lu, D. E. Mcnally, M. Moretti Sala, Jsaminka Terzic, M. H. Upton, D. Casa, G. Ingold, Gang Cao, T. Schmitt
Physics and Astronomy Faculty Publications
We use resonant elastic and inelastic x-ray scattering at the Ir-L3 edge to study the doping-dependent magnetic order, magnetic excitations, and spin-orbit excitons in the electron-doped bilayer iridate (Sr1−xLax)3Ir2O7 (0 ≤ x ≤ 0.065). With increasing doping x, the three-dimensional long range antiferromagnetic order is gradually suppressed and evolves into a three-dimensional short range order across the insulator-to-metal transition from x = 0 to 0.05, followed by a transition to two-dimensional short range order between x = 0.05 and 0.065. Because of the interactions between the J …
Simultaneous Metal-Insulator And Antiferromagnetic Transitions In Orthorhombic Perovskite Iridate Sr0.94Ir0.78O2.68 Single Crystals, Hao Zheng, Jsaminka Terzic, Feng Ye, X. G. Wan, D. Wang, Jinchen Wang, Xiaoping Wang, P. Schlottmann, Shujuan Yuan, Gang Cao
Simultaneous Metal-Insulator And Antiferromagnetic Transitions In Orthorhombic Perovskite Iridate Sr0.94Ir0.78O2.68 Single Crystals, Hao Zheng, Jsaminka Terzic, Feng Ye, X. G. Wan, D. Wang, Jinchen Wang, Xiaoping Wang, P. Schlottmann, Shujuan Yuan, Gang Cao
Center for Advanced Materials Faculty Publications
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 Sr0.94Ir0.78O2.68 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 …
Anisotropic Softening Of Magnetic Excitations In Lightly Electron-Doped Sr2Iro4, X. Liu, M. P. M. Dean, Z. Y. Meng, M. H. Upton, T. Qi, T. Gog, Y. Cao, J. Q. Lin, D. Meyers, H. Ding, Gang Cao, J. P. Hill
Anisotropic Softening Of Magnetic Excitations In Lightly Electron-Doped Sr2Iro4, X. Liu, M. P. M. Dean, Z. Y. Meng, M. H. Upton, T. Qi, T. Gog, Y. Cao, J. Q. Lin, D. Meyers, H. Ding, Gang Cao, J. P. Hill
Center for Advanced Materials Faculty Publications
The magnetic excitations in electron-doped (Sr1−xLax)2IrO4 with x = 0.03 were measured using resonant inelastic x-ray scattering at the Ir L3 edge. Although much broadened, well defined dispersive magnetic excitations were observed. Comparing with the magnetic dispersion from the undoped compound, the evolution of the magnetic excitations upon doping is highly anisotropic. Along the antinodal direction, the dispersion is almost intact. On the other hand, the magnetic excitations along the nodal direction show significant softening. These results establish the presence of strong magnetic correlations in electron-doped (Sr1−xLax …
Pressure-Induced Confined Metal From The Mott Insulator Sr3Ir2O7, Yang Ding, Liuxiang Yang, Cheng-Chien Chen, Heung-Sik Kim, Myung Joon Han, Wei Luo, Zhenxing Feng, Mary Upton, Diego Casa, Jungho Kim, Thomas Gog, Zhidan Zeng, Gang Cao, Ho-Kwang Mao, Michel Van Veenendaal
Pressure-Induced Confined Metal From The Mott Insulator Sr3Ir2O7, Yang Ding, Liuxiang Yang, Cheng-Chien Chen, Heung-Sik Kim, Myung Joon Han, Wei Luo, Zhenxing Feng, Mary Upton, Diego Casa, Jungho Kim, Thomas Gog, Zhidan Zeng, Gang Cao, Ho-Kwang Mao, Michel Van Veenendaal
Physics and Astronomy Faculty Publications
The spin-orbit Mott insulator Sr3Ir2O7 provides a fascinating playground to explore insulator-metal transition driven by intertwined charge, spin, and lattice degrees of freedom. Here, we report high-pressure electric resistance and resonant inelastic x-ray scattering measurements on single-crystal Sr3Ir2O7 up to 63–65 GPa at 300 K. The material becomes a confined metal at 59.5 GPa, showing metallicity in the ab plane but an insulating behavior along the c axis. Such an unusual phenomenon resembles the strange metal phase in cuprate superconductors. Since there is no sign of the collapse of spin-orbit …