Electronic structure of topological materials probed by angle-resolved photoemission spectroscopy

• Ano de defesa: 2021
• Autor(a) principal: Pedro Henrique Rezende Gonçalves
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Minas Gerais; Brasil; ICX - DEPARTAMENTO DE FÍSICA; Programa de Pós-Graduação em Física; UFMG
• Palavras-chave em Português: Topological insulators; Weyl semimetals; Charge-density waves; Angle-resolved photoemission spectroscopy; Estrutura eletrônica; Semimetais; Fotoemissão; Ondas de densidade de carga
• Link de acesso: http://hdl.handle.net/1843/38460; https://orcid.org/ 0000-0001-6773-8921

The research in topological materials had been an extensive source for prediction and observation of new and exotic phenomena at the condensed matter level. During the last 20 years, a variety of new topological phases of matter had emerged. The most prominent are Topological Insulators and Weyl Semimetals. In this thesis, we used Angle-resolved Photoemission Spectroscopy to characterize the electronic structure of two topological materials: the quaternary topological insulator BiSbSe2.5Te0.5 and the topological Weyl semimetal candidate TaTe4. We reported the realization of a stable quaternary topological insulator, BiSbSe2.5Te0.5, characterized by a positive doping and charge carriers with smaller effective mass when compared with Bi2Se3. About TaTe4, we report a 2D Fermi surface composed by four Dirac/Weyl cones in the surface first Brillouin zone. The electronic structure of these metallic states is compatible with previous findings in the literature, showing a coexistence of CDW and topological features in a 2D Fermi surface.