Gatti, G.Gosalbez-Martinez, D.Tsirkin, S. S.Fanciulli, M.Puppin, M.Polishchuk, S.Moser, S.Testa, L.Martino, E.Roth, S.Bugnon, PhMoreschini, L.Bostwick, A.Jozwiak, C.Rotenberg, E.Di Santo, G.Petaccia, L.Vobornik, IFujii, J.Wong, J.Jariwala, D.Atwater, H. A.Ronnow, H. M.Chergui, M.Yazyev, O., VGrioni, M.Crepaldi, A.2020-12-032020-12-032020-12-032020-11-1910.1103/PhysRevLett.125.216402https://infoscience.epfl.ch/handle/20.500.14299/173848WOS:000590412500009Trigonal tellurium, a small-gap semiconductor with pronounced magneto-electric and magneto-optical responses, is among the simplest realizations of a chiral crystal. We have studied by spin- and angle-resolved photoelectron spectroscopy its unconventional electronic structure and unique spin texture. We identify Kramers-Weyl, composite, and accordionlike Weyl fermions, so far only predicted by theory, and show that the spin polarization is parallel to the wave vector along the lines in k space connecting high-symmetry points. Our results clarify the symmetries that enforce such spin texture in a chiral crystal, thus bringing new insight in the formation of a spin vectorial field more complex than the previously proposed hedgehog configuration. Our findings thus pave the way to a classification scheme for these exotic spin textures and their search in chiral crystals.Physics, MultidisciplinaryPhysicstext::journal::journal article::research article