Extreme magnetoresistance and pressure-induced superconductivity in the topological semimetal candidate YBi
Extreme magnetoresistance and pressure-induced superconductivity in the topological semimetal candidate YBi
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DOI：
10.1103/physrevb.99.024110
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发表时间：
2019-01
影响因子：
3.7
通讯作者：
C. Xu;Bin Li;M. V. Delft;W. Jiao;Wei Zhou;B. Qian;Nikolai Zhigadlo;D. Qian;R. Sankar
中科院分区：
文献类型：
--
作者：
C. Xu;Bin Li;M. V. Delft;W. Jiao;Wei Zhou;B. Qian;Nikolai Zhigadlo;D. Qian;R. Sankar
拓扑材料中的超导性，无论是在环境条件下还是在极端条件下，都一直吸引着科学家们，因为它是实现拓扑超导性的有希望的候选者，是在凝聚态物质中承载长期寻找的马约拉纳费米子的平台。最近在稀土单晶中发现的极大磁阻（XMR）为寻找其中的拓扑非平凡态开辟了一条新的途径，尽管相反的观点认为是载流子补偿效应导致了观察到的巨大的非饱和磁阻。本文研究了拓扑非平凡候选YBi的量子振荡和压力诱导超导性。虽然磁输运和量子振荡确实揭示了几乎补偿的载流子，但第一性原理计算清楚地表明，电子表面态表现出拓扑上的非平凡特征。施加静水压力后，材料的磁阻减小，并产生超导性。然而，在相图中存在着XMR和超导共存的状态。因此，YBi可能是研究XMR，拓扑态和超导性之间相互作用的罕见系统。
Superconductivity in topological materials, either at ambient or extreme conditions, has continued to intrigue scientists as a promising candidate for realizing topological superconductivity, a platform to host the long-sought Majorana fermions in condensed matter. The recent discovery of extremely large magnetoresistance (XMR) in the rare-earth monopnictides opens a new avenue to search for topologically nontrivial states therein, although contrasting opinions argue that it is the carrier compensation effect that is responsible for the observed large, nonsaturating magnetoresistance. Here we study the quantum oscillations and pressure-induced superconductivity in the topologically nontrivial candidate YBi. While the magnetotransport and quantum oscillations do reveal nearly compensated charge carriers, first-principles calculations clearly show that the electronic surface states manifest topologically nontrivial features. Upon applying external hydrostatic pressures, the magnetoresistance is found to decrease and atGPa, superconductivity emerges. There exists, however, a regime where XMR and superconductivity coexist in the phase diagram. YBi may therefore represent a rare system for studying the interplay between XMR, topological states, and superconductivity.