| 研究実績の概要 |
We mainly investigated three different materials: monolayer blue phosphene, monolayer GdAg2 and single crystal LaBi.
Monolayer blue phosphene is grown by evaporating pieces of black phosphene onto a clean Au(111) substrate. From the LEED pattern, we find a perfect 5x5 superstructure, which is in good agreement with previous reports. The ARPES measurements have confirmed the existence of a band gap near the Fermi level. So blue phosphene is a good candidate for future nanodevices. The manuscript is still under preparation.
Monolayer GdAg2 is grown by evaporating pure Gd from a e-beam evaporator onto a clean Ag(111) substrate. Previous MOKE and XMCD measurements have confirmed the ferromagnetic order in this material. Here, using ARPES, we found the existence of a Weyl nodal line in this material. Our theoretical collaborator confirmed our findings. Now, the manuscript has been submitted and is under review.
LaBi is a topological insulator candidate. Previous experiments have reported some ARPES results on the band structures and concluded that LaBi have topological Dirac cones. However, here we studied the surface states of LaBi by high-resolution ARPES and first-principles calculations. We found that the otherwise topological nontrivial surface states are gapped out by band hybridization and the surface states looks like a Dirac nodal line. This work has already been published in Physical Review B. [Phys. Rev. B 97, 155153 (2018)]
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