论文标题
压力诱导的旋转摩托绝缘子GATA4SE8中的拓扑超导性
Pressure Induced Topological Superconductivity in the Spin-Orbit Mott Insulator GaTa4Se8
论文作者
论文摘要
Lacunar Spinel Gata $ _4 $ SE $ _8 $是Molecular $ j _ {\ text {eff}} \！= \！3/2 $状态的旋转轨道耦合莫特绝缘子的独特示例。在压力下，它在t $ _c $ = 5.8k的情况下变成了超导，而无需掺杂。在这项工作中，我们表明，这种压力诱导的超导性是一种以旋转2库珀对为特征的新型拓扑相的实现。从第一原理密度的功能计算和随机相位近似开始，我们构建了微观模型并执行详细的分析。发现施加压力是可以触发通过强烈的hund耦合辅助的虚拟间间隧道过程，从而稳定了特定的$ d $ - 波五重奏通道。此外，我们表明其Bogoliubov准粒子及其表面状态具有新颖的拓扑性质。为了验证我们的理论，我们提出了可以通过约瑟夫森连接运输和扫描隧道显微镜来衡量的独特实验特征。我们的发现打开了新的方向，以寻找自旋轨道耦合材料中的异国情调超导性。
Lacunar spinel GaTa$_4$Se$_8$ is a unique example of spin-orbit coupled Mott insulator described by molecular $j_{\text{eff}}\!=\!3/2$ states. It becomes superconducting at T$_c$=5.8K under pressure without doping. In this work, we show, this pressure-induced superconductivity is a realization of a new type topological phase characterized by spin-2 Cooper pairs. Starting from first-principles density functional calculations and random phase approximation, we construct the microscopic model and perform the detailed analysis. Applying pressure is found to trigger the virtual interband tunneling processes assisted by strong Hund coupling, thereby stabilizing a particular $d$-wave quintet channel. Furthermore, we show that its Bogoliubov quasiparticles and their surface states exhibit novel topological nature. To verify our theory, we propose unique experimental signatures that can be measured by Josephson junction transport and scanning tunneling microscope. Our findings open up new directions searching for exotic superconductivity in spin-orbit coupled materials.
