[理论室报告] Pr2Ir2O7: when Luttinger semimetal meets Melko-Hertog-Gingras spin state
摘要：We study the band structure topology and engineering from the interplay between local moments and itinerant electrons in the context of pyrochlore iridates. For the metallic iridate Pr2Ir2O7, the Ir 5d conduction electrons interact with the Pr 4f local moments via the f-d exchange. While the Ir electrons form a Luttinger semimetal, the Pr moments can be tuned into an ordered spin ice with a finite ordering wavevector, dubbed “Melko-Hertog-Gingras” state, by varying Ir and O contents. We point out that the ordered spin ice of the Pr local moments generates an internal magnetic field that reconstructs the band structure of the Luttinger semimetal. Besides the broad existence of Weyl nodes, we predict that the magnetic translation of the “Melko-Hertog-Gingras” state for the Pr moments protects the Dirac band touching at certain time reversal invariant momenta for the Ir conduction electrons. We propose the magnetic fields to control the Pr magnetic structure and thereby indirectly influence the topological and other properties of the Ir electrons. Our prediction may be immediately tested in the ordered Pr2Ir2O7 samples. We expect our work to stimulate a detailed examination of the band structure, magneto-transport, and other properties of Pr2Ir2O7.
参考文献： Xu-Ping Yao, Gang Chen, arXiv:1712.06534
关于报告人：Dr. Gang Chen received his PhD with Leon Balents at UC Santa Barbara and then hold independent postdoc positions at CU Boulder and Univ of Toronto. He was appointed Professor of Physics at Fudan University in Winter 2014 and started the position in Summer 2015. He has a broad interest in strongly correlated systems, and his works are mostly experimentally motivated.