Observation of Topological Surface State in High Temperature Superconductor MgB2

Abstract

The hunt for the benchmark topological superconductor (TSc) has been an extremely active research subject in condensed matter research, with quite a few candidates identified or proposed. However, low transition temperatures (Tc) and/or strong sensitivity to disorder and dopant levels in known TSc candidates have greatly hampered progress in this field. Here, we use Angle-resolved Photoemission Spectroscopy (ARPES) to show the presence of Dirac Nodal Lines (DNLs) and the corresponding topological surface states (TSS's) on the [010] faces of the Tc=39K s-wave BCS superconductor MgB2. Not only is this nearly triple the current record of superconducting Tc among all candidate TSc's, but the nature of these DNL states should make them highly tolerant against disorder and inadvertent doping variations. This makes MgB2 a promising high temperature platform for the study of topological superconductivity.

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Cited by in corpus (8)

• Electronic structure of quantum materials studied by angle-resolved photoemission spectroscopy
• Superconductivity in TlBi${}_2$ with a large Kadowaki-Woods ratio
• Superconducting properties of the spin Hall candidate Ta3Sb with eightfold degeneracy
• Topological superconductor candidates PdBi${}_2$Te${}_4$ and PdBi${}_2$Te${}_5$ from a generic ab initio strategy
• A first-principles investigation of the origin of superconductivity in TlBi${}_2$
• Experimental detection of topological electronic state and large linear magnetoresistance in $SrS{n}_4$ superconductor
• High-pressure high-temperature solution growth, structural, and superconducting properties of Fe-substituted MgB2 single crystals
• Spectroscopic Evidence on Realization of a Genuine Topological Nodal Line Semimetal in LaSbTe