title: Odd-parity magnetoresistance in pyrochlore iridate thin films with broken time-reversal symmetry.
abstract: A new class of materials termed topological insulators have been intensively investigated due to their unique Dirac surface state carrying dissipationless edge spin currents. Recently, it has been theoretically proposed that the three dimensional analogue of this type of band structure, the Weyl Semimetal phase, is materialized in pyrochlore oxides with strong spin-orbit coupling, accompanied by all-in-all-out spin ordering. Here, we report on the fabrication and magnetotransport of Eu2Ir2O7 single crystalline thin films. We reveal that one of the two degenerate all-in-all-out domain structures, which are connected by time-reversal operation, can be selectively formed by the polarity of the cooling magnetic field. Once formed, the domain is robust against an oppositely polarised magnetic field, as evidenced by an unusual odd field dependent term in the magnetoresistance and an anomalous term in the Hall resistance. Our findings pave the way for exploring the predicted novel quantum transport phenomenon at the surfaces/interfaces or magnetic domain walls of pyrochlore iridates.
authors.affiliation: Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656, Japan.
authors.forename: T C
authors.initials: TC
authors.lastname: Fujita
authors.affiliation: Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kozuka
authors.affiliation: Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Uchida
authors.affiliation: 1] Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656, Japan [2] Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan [3] PRESTO, Japan Science and Technology Agency (JST), Tokyo 102-0075, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Tsukazaki
authors.affiliation: 1] Department of Advanced Materials Science, University of Tokyo, Kashiwa 277-8561, Japan [2] RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Arima
authors.affiliation: 1] Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656, Japan [2] RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kawasaki