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Charge Carrier Transport with Low-Temperature Anomalies in Engineered 4d5 Oxide Superlattices of (Sr2IrO4)4/(Sr3Ru2O27)N



Hui Xu, Alexander Grutter, Zhangzhang Cui, Zhicheng Wang, Xiaofang Zhai, Yalin Lu


We report tunable conduction behavior of a series of (Sr2IrO4)4/(Sr3Ru2O27)N (N=1, 2, 4) atomic layer superlattices, in which itinerant electron, itinerant hole and localized electron transports can be varied dependent on the period. Furthermore, we find a temperature-dependent transition from itinerant-electron to itinerant hole and to an anomalous charge localized phase region. Specifically, for the N=4 superlattice, the electron to hole transition occurs at a temperature of 35 K, at which temperature the sample behaves as an intrinsic insulator without either electrons or holes. Further reducing the temperature to below 16 K, the superlattice enters an anomalous phase region, in which an abrupt zero to negative magnetoresistance transition and a hall resistivity kink are observed at a critical field near 1.5 T. Above the critical field, polarized neutron reflectivity measurements revealed ferromagnetism confined in the Sr3Ru2O7 layers. Moreover, the N=2 superlattice exhibit a strong hall resistivity peak at 1.5 T which may be an indication of the topological Hall effect. We demonstrate the 4d5 oxide superlattice as a powerful platform in engineering exotic types of phase transitions that are unexplored in thin film or bulk samples.
Physical Review B


Xu, H. , Grutter, A. , Cui, Z. , Wang, Z. , Zhai, X. and Lu, Y. (2020), Charge Carrier Transport with Low-Temperature Anomalies in Engineered 4d5 Oxide Superlattices of (Sr<sub>2</sub>IrO<sub>4</sub>)<sub>4</sub>/(Sr<sub>3</sub>Ru<sub>2</sub>O<sub>27</sub>)<sub>N</sub>, Physical Review B, [online], (Accessed April 23, 2024)
Created April 29, 2020, Updated October 12, 2021