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arXiv · 1703.10008

Triplet Fermions and Dirac Fermions in Borophene

Motohiko Ezawa
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Abstract

Borophene is a monolayer materials made of boron. A perfect planar boropehene called $\beta_{12}$ borophene has Dirac cones and they are well reproduced by a tight-binding model according to recent experimental and first-principles calculation results. We explicitly derive a Dirac theory for them. Dirac cones are gapless when the inversion symmetry exists, while they are gapped when it is broken. In addition, three-band touching points emerge together with pseudospin triplet fermions when all transfer energy is equal and all on-site energy is equal. The three-band touching is slightly resolved otherwise. We construct effective three-band theories for triplet fermions. We also study the edge states of borophene nanoribbons, which show various behaviors depending on the way of edge terminations.

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Motohiko Ezawa. 2017-03-29. Triplet Fermions and Dirac Fermions in Borophene. https://doi.org/10.1103/physrevb.96.035425

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