Dirac-semimetal phase diagram of two-dimensional black phosphorus

作者：Doh Hyeonjin; Choi Hyoung Joon^*

来源：2D Materials, 2017, 4(2): 025071.

DOI：10.1088/2053-1583/aa6835

• black phosphorus
• band gap closing
• Dirac semimetal
• phase diagram

Black phosphorus (BP), a layered van der Waals material, reportedly has a band gap sensitive to external perturbations and manifests a Dirac-semimetal phase when its band gap is closed. Previous studies were focused on effects of each perturbation, lacking a unified picture for the band-gap closing and the Dirac-semimetal phase. Here, using pseudospins from the glide-reflection symmetry, we study the electronic structures of mono- and bilayer BP and construct the phase diagram of the Dirac-semimetal phase in the parameter space related to pressure, strain, and electric field. We find that the Dirac-semimetal phase in BP layers is singly connected in the phase diagram, indicating the phase is topologically identical regardless of the gap-closing mechanism. Our findings can be generalized to the Dirac-semimetal phase in anisotropic layered materials and can play a guiding role in search for a new class of topological materials and devices.

• 出版日期2017-6