Kobayashi Takahiro, Toichi Yuichiro, Yaji Koichiro, Nakata Yoshitaka, Yaoita Yuchi, Iwaoka Mutsuki, Koga Mariko, Zhang Yituo, Fujii Jun, Ono Shimpei, Sassa Yasmine, Yoshida Yasuo, Hasegawa Yukio, Komori Fumio, Shin Shik, Ichinokura Satoru, Akiyama Ryota, Hasegawa Shuji, Shishidou Tatsuya, Weinert Michael, Sakamoto Kazuyuki
Department of Material and Life Science, Osaka University, Osaka 565-0871, Japan.
Department of Applied Physics, Osaka University, Osaka 565-0871, Japan.
Nano Lett. 2023 Aug 23;23(16):7675-7682. doi: 10.1021/acs.nanolett.3c02387. Epub 2023 Aug 14.
The interplay of spin-orbit coupling and crystal symmetry can generate spin-polarized bands in materials only a few atomic layers thick, potentially leading to unprecedented physical properties. In the case of bilayer materials with global inversion symmetry, locally broken inversion symmetry can generate degenerate spin-polarized bands, in which the spins in each layer are oppositely polarized. Here, we demonstrate that the hidden spins in a Tl bilayer crystal are revealed by growing it on Ag(111) of sizable lattice mismatch, together with the appearance of a remarkable phenomenon unique to centrosymmetric hidden-spin bilayer crystals: a novel band splitting in both spin and space. The key to success in observing this novel splitting is that the interaction at the interface has just the right strength: it does not destroy the original wave functions of the Tl bilayer but is strong enough to induce an energy separation.
自旋轨道耦合与晶体对称性的相互作用能够在仅几个原子层厚的材料中产生自旋极化能带，这有可能带来前所未有的物理性质。对于具有全局反演对称性的双层材料而言，局部反演对称性破缺会产生简并的自旋极化能带，其中每一层中的自旋具有相反的极化方向。在此，我们证明，通过在具有相当大晶格失配的Ag(111)上生长Tl双层晶体，其隐藏自旋得以揭示，同时还出现了中心对称隐藏自旋双层晶体所特有的显著现象：在自旋和空间上都出现了一种新型能带分裂。成功观测到这种新型分裂的关键在于界面处的相互作用具有恰到好处的强度：它不会破坏Tl双层的原始波函数，但又足够强以诱导出能量分离。
