Skyrme Insulators: Insulators at the Brink of Superconductivity

Onur Erten, Po-Yao Chang, Piers Coleman, Alexei Tsvelik

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Current theories of superfluidity are based on the idea of a coherent quantum state with topologically protected quantized circulation. When this topological protection is absent, as in the case of 3He-A, the coherent quantum state no longer supports persistent superflow. Here, we argue that the loss of topological protection in a superconductor gives rise to an insulating ground state. We specifically introduce the concept of a Skyrme insulator to describe the coherent dielectric state that results from the topological failure of superflow carried by a complex-vector order parameter. We apply this idea to the case of SmB6, arguing that the observation of a diamagnetic Fermi surface within an insulating bulk can be understood as a realization of this state. Our theory enables us to understand the linear specific heat of SmB6 in terms of a neutral Majorana Fermi sea and leads us to predict that in low fields of order a Gauss, SmB6 will develop a Meissner effect.
Original languageEnglish
Article number057603
Pages (from-to)1-6
Number of pages6
JournalPhysical Review Letters
Issue number5
Publication statusPublished - 4 Aug 2017

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