Relativistic fermions in designer curved space

Pancharatnam-Berry phase and kinetic magnetoelectric effect in trigonal tellurium. Novel family of chiral-based topological insulators: elemental tellurium under strain. Gyrotropic effects in trigonal tellurium studied from first principles. Band splitting and Weyl nodes in trigonal tellurium studied by angle-resolved photoemission spectroscopy and density functional theory. Weyl node and spin texture in trigonal tellurium and selenium. Hirayama, M., Okugawa, R., Ishibashi, S., Murakami, S. Discovery of Weyl fermion semimetals and topological Fermi arc states. Weyl and Dirac semimetals in three-dimensional solids. Experimental observation of the quantum Hall effect and BerryвЂ™s phase in graphene. Two-dimensional gas of massless Dirac fermions in graphene. Our work expands the spectrum of Weyl matter into semiconductors and offers a new platform to design novel quantum devices by marrying the advantages of topological materials to versatile semiconductors.

We synthesize high-quality n-type tellurene by a hydrothermal method with subsequent dielectric doping and detect a topologically non-trivial ПЂ Berry phase in quantum Hall sequences. Tellurene, the two-dimensional form of tellurium, possesses a chiral crystal structure which induces unconventional Weyl nodes with a hedgehog-like radial spin texture near the conduction band edge. Here, we report the first experimental observation of Weyl fermions in a semiconductor. However, most Dirac/Weyl nodes generically exist in semimetals without exploitable band gaps due to their accidental band-crossing origin. Under strong magnetic fields, the topological properties of Dirac/Weyl materials can directly be observed through quantum Hall states. Dirac and Weyl nodal materials can host low-energy relativistic quasiparticles.

Relativistic fermions in designer curved space