Proximity effect and Ising superconductivity in superconductor/transition metal dichalcogenide heterostructures

Recently, it was experimentally realized that 2D superconducting transition metal dichalcogenides (TMD) such as gated MoS\(_2\) and monolayer NbSe\(_2\) have in-plane upper critical magnetic fields much higher than the Pauli limit. This is due to the so-called Ising spin-orbit coupling (SOC) of TMD...

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Bibliographic Details
Published inarXiv.org
Main Authors Wakatsuki, Ryohei, Law, K T
Format Paper
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 17.04.2016
Subjects
Chalcogenides
Cooper pairs
Electron spin
Heterostructures
Ising model
Magnetic fields
Proximity effect (electricity)
Spin-orbit interactions
Superconductivity
Superconductors
Topological superconductors
Transition metal compounds
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Summary:Recently, it was experimentally realized that 2D superconducting transition metal dichalcogenides (TMD) such as gated MoS\(_2\) and monolayer NbSe\(_2\) have in-plane upper critical magnetic fields much higher than the Pauli limit. This is due to the so-called Ising spin-orbit coupling (SOC) of TMD which pins the electron spins along the out-of-plane directions and protects the Cooper pairs from in-plane magnetic fields. However, many TMD materials with extremely large Ising SOC, in the order of a few hundred meV, are not superconducting. In this work, we show that TMD materials can induce strong Ising SOC on ordinary \(s\)-wave superconductors through proximity effect. By solving the self-consistent gap equation of the TMD/superconductor heterostructure, we found that the \(H_{c2}\) of the \(s\)-wave superconductor can be strongly enhanced. Importantly, when the in-plane field is larger than the Pauli limit field and weaker than \(H_{c2}\), the heterostructure becomes a nodal topological superconductor which supports Majorana flat bands.
ISSN:2331-8422