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Free keywords:
Bismuth alloys, Critical current density (superconductivity), Crystal structure, Electronic structure, Energy gap, Magnesium alloys, Magnesium metallography, Photoelectron spectroscopy, Potassium alloys, Scanning tunneling microscopy, Ternary alloys, Critical state, Dirac fermions, Flat band, Small bandgap, Systematic study, Bismuth metallography
Abstract:
Dirac semimetals are classified into different phases based on the types of Dirac fermions. Tuning the transition among different types of Dirac fermions in one system remains a challenge. Recently, KMgBi was predicted to be located at a critical state in which various types of Dirac fermions can be induced owing to the existence of a flatband. Here, we carried out systematic studies on the electronic structure of KMgBi single crystals by combining angle-resolve photoemission spectroscopy and scanning tunneling microscopy/spectroscopy. The flatband was clearly observed near the Fermi level. We also revealed a small bandgap of ∼20 meV between the flatband and the conduction band. These results demonstrate the critical states of KMgBi that transition among various types of Dirac fermions can be tuned in one system. © 2021 Author(s).
