D. D. Liang

Enhanced electrical conductivity and diluted Ir4+ spin orders in electron doped iridates Sr2–xGaxIrO4

Sr2IrO4 represents a fascinating system to study comparable electronic correlations and spin-orbit couplings, and recently attracts considerable attention in high-temperature superconductivity. Here, we report on the transport and magnetic properties in gallium-doped Sr2IrO4. A metallic state is discovered when doping x is over 0.1, which could be understood in terms of the quickly decreased energy gap and increased carrier concentration. In addition to the high-temperature magnetic transition (TCu2009>u2009200u2009K), a low-temperature one ( TC′) is also observed for the xu2009=u20090.05–0.10 samples. Both of the magnetic states are found to be canted antiferromagnetism. The low-temperature phase is strongly depressed by doping and vanishes when doping is further increased, which is probably stabilized by the long-way exchange interactions of diluted Ir4+ spins via Ir3+ ions. Our studies provide an insight into the electrical and magnetic states tuned by chemical doping in Sr2IrO4, thereby facilitating the seeking of superc...

Extreme magnetoresistance and Shubnikov-de Haas oscillations in ferromagnetic DySb

The electronic structures of a representative rare earth monopnictide (i.e., DySb) under high magnetic field (i.e., in the ferromagnetic state) are studied from both experimental and theoretical aspects. A non-saturated extremely large positive magnetoresistance (XMR) is observed (as large as 3.7*10^4% at 1.8 K and 38.7 T), along with the Shubnikov-de Haas oscillations that are well reproduced by our first principles calculations. Three possible origins of XMR are examined. Although a band inversion is found theoretically, suggesting that DySb might be topologically nontrivial, it is deeply underneath the Fermi level, which rules out a topological nature of the XMR. The total densities of electron-like and hole-like carriers are not fully compensated, showing that compensation is unlikely to account for the XMR. The XMR is eventually understood in terms of high mobility that is associated with the steep linear bands. This discovery is important to the intensive studies on the XMR of rare earth monopnictides.