Pressure and magnetic-field effects on metal-insulator transitions of bulk and domain-wall states in pyrochlore iridates

Abstract

We have explored the critical metal-insulator phenomena for pyrochlore-type $R_2$Ir${}_2$O${}_7$, in which electron correlation strength and magnetic configuration are systematically controlled by varying the average rare-earth ionic radius ($R$=Nd${}_{1-x}$Pr${}_x$ and Sm${}_y$Nd${}_{1-y}$), external pressure, and magnetic field. Metal-insulator transitions in bulk are caused by increasing $x$ or tuning external pressure, indicating that the effective electron correlation is responsible for the transition. The metallic state intervenes between the paramagnetic insulating and antiferromagnetically ordered insulating phases for \SNIO ($y$=0.7-0.9), reminiscent of the first-order Mott transition. Furthermore, the metal-to-insulator crossover is observed (around $y$=0.7) for the charge transport on magnetic domain walls in the insulating bulk. An application of magnetic field also drives metal-insulator transitions for \NPIO in which a variety of exotic topological quantum states are potentially realized.

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• Competing orders and topology in the global phase diagram of pyrochlore iridates
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• Unconventional anomalous Hall effect from antiferromagnetic domain walls of Nd2Ir2O7 thin films
• All-in-all-out magnetic domain wall conduction in pyrochlore iridate heterointerface
• Topological Properties and Functionalities in Oxide Thin Films and Interfaces
• Dilute stuffing in the pyrochlore iridate $E{u}_{2}I{r}_2{O}_7$
• All-in-all-out magnetic domain size in pyrochlore iridate thin films as probed by local magnetotransport
• Strain engineered higher order topological phases for spin-3/2 Luttinger fermions
• Modulated Helical Metals at Magnetic Domain Walls of Pyrochlore Iridium Oxides
• Robustness of anomaly-related magnetoresistance in doped Weyl semimetals
• Influence of hydrostatic pressure on the bulk magnetic properties of Eu${}_2$Ir${}_2$O${}_7$
• Shape of magnetic domain walls formed by coupling to mobile charges
• Strongly-coupled quantum critical point in an all-in-all-out antiferromagnet
• Evolution of structure and magnetism across the metal-insulator transition in the pyrochlore iridate $($Nd${}_{1-x}$Ca${}_x{)}_2$Ir${}_2$O${}_7$
• Stability of the Weyl-semimetal phase on the pyrochlore lattice
• Competing magnetic orders and multipolar Weyl fermions in 227 pyrochlore iridates
• Monopole-limited nucleation of magnetism in Eu${}_2$Ir${}_2$O${}_7$
• Magnetotransport of single crystal Sm${}_2$Ir${}_2$O${}_7$ across the pressure-induced quantum-critical phase boundary
• Mapping the structural, magnetic and electronic behavior of (Eu${}_{1-x}$Ca${}_x$)${}_2$Ir${}_2$O${}_7$ across a metal-insulator transition
• Metal-insulator transitions in pyrochlore oxides