Asymmetric mass acquisition in LaBi: Topological semimetal candidate

作者：Wu Yun; Kong Tai; Wang Lin Lin; Johnson D D; Mou Daixiang; Huang Lunan; Schrunk Benjamin; Bud'ko S L; Canfield P C^*; Kaminski Adam^*

来源：Physical Review B, 2016, 94(8): 081108.

DOI：10.1103/PhysRevB.94.081108

We use our high resolution He-lamp-based, tunable laser-based angle-resolved photoemission spectroscopy measurements and density functional theory calculations to study the electronic properties of LaBi, a binary system that was proposed to be a member of a new family of topological semimetals. Both bulk and surface bands are present in the spectra. The dispersion of the surface state is highly unusual. It resembles a Dirac cone, but upon closer inspection we can clearly detect an energy gap. The bottom band follows roughly a parabolic dispersion. The dispersion of the top band remains very linear, "V" -shape like, with the tip approaching very closely to the extrapolated location of Dirac point. Such asymmetric mass acquisition is highly unusual and opens a possibility of a new topological phenomenon that has yet to be understood.

• 出版日期2016-8-18