Radial spin texture in elemental tellurium with chiral crystal structure

Trigonal tellurium has a chiral crystal structure which is characterized by a lack of mirror symmetry and an inversion center, resulting in the inequivalent right- and left-handed structures. To reveal the spin textures of chiral crystals, here we investigate the spin and electronic structure in p-type semiconductor elemental tellurium 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 momentum of electron 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 hedgehog-like, leading to unconventional magnetoelectric effects and nonreciprocal phenomena.