Sakano M, Hirayama M, Takahashi T, Akebi S, Nakayama M, Kuroda K, Taguchi K, Yoshikawa T, Miyamoto K, Okuda T, Ono K, Kumigashira H, Ideue T, Iwasa Y, Mitsuishi N, Ishizaka K, Shin S, Miyake T, Murakami S, Sasagawa T, Kondo Takeshi
Institute for Solid State Physics (ISSP), The University of Tokyo, Kashiwa 277-8581, Japan.
Quantum-Phase Electronics Center (QPEC) and Department of Applied Physics, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan.
Phys Rev Lett. 2020 Apr 3;124(13):136404. doi: 10.1103/PhysRevLett.124.136404.
The chiral crystal is characterized by a lack of mirror symmetry and inversion center, resulting in the inequivalent right- and left-handed structures. In the noncentrosymmetric crystal structure, the spin and momentum of electrons are expected to be locked in the reciprocal space with the help of the spin-orbit interaction. To reveal the spin textures of chiral crystals, we investigate the spin and electronic structure in a p-type semiconductor, elemental tellurium, with the simplest chiral structure by using spin- and angle-resolved photoemission spectroscopy. Our data demonstrate that the highest valence band crossing the Fermi level has a spin component parallel to the electron momentum around the Brillouin zone corners. Significantly, we have also confirmed that the spin polarization is reversed in the crystal with the opposite chirality. The results indicate that the spin textures of the right- and left-handed chiral crystals are hedgehoglike, leading to unconventional magnetoelectric effects and nonreciprocal phenomena.
手性晶体的特征是缺乏镜面对称性和反演中心，导致左右手结构不等价。在非中心对称晶体结构中，电子的自旋和动量有望借助自旋轨道相互作用在倒易空间中锁定。为了揭示手性晶体的自旋纹理，我们通过使用自旋和角分辨光电子能谱，研究了具有最简单手性结构的p型半导体碲中的自旋和电子结构。我们的数据表明，穿过费米能级的最高价带在布里渊区角附近具有与电子动量平行的自旋分量。值得注意的是，我们还证实，在手性相反的晶体中自旋极化会反转。结果表明，左右手性晶体的自旋纹理呈刺猬状，导致非常规的磁电效应和非互易现象。
