There are phases of matter whose electronic properties are closely related to the topology of their band structure. One of these properties was first observed by Klaus von Klitzing in 1980 when he discovered that the Hall resistance in two-dimensional electron systems can be quantized exactly (quantum Hall effect). Since then, numerous phases with properties related to the topology of their electronic structure have been discovered, such as topological insulators, topological semimetals, and topological superconductors, among others. One of the most interesting properties of these new phases is that they possess low-energy excitations (quasiparticles) that can behave like Dirac fermions, Weyl fermions, or Majorana fermions.
The combination of condensed matter physics, which studies the properties of matter in its solid and liquid states, with topology, which mathematically studies the properties of spaces or objects that remain invariant under any continuous transformation, has allowed for the connection of new macroscopic quantum properties with certain topological phases. The importance of this new field of materials science was recognized in 2016 when the Nobel Prize in Physics was awarded to David J. Thouless, F. Duncan Haldane, and J. Michael Kosterlitz “for theoretical discoveries of topological phase transitions and topological phases of matter.”
The objective of this line of research is to study the most basic characteristics of topological quantum systems, their robustness in the presence of atomic disorder, and the effects of interacting with other systems. To this end, we develop theoretical models based on effective Hamiltonians and analyze the electronic structure through calculations based on Density Functional Theory and the Tight-Binding model.
Artículos destacados:
- O. Arroyo-Gascón, Y. Baba, J. I. Cerdá, Ó. de Abril, R. Martínez, F. Domínguez-Adame, L. Chico, “Persistence of symmetry-protected Dirac points at the surface of the topological crystalline insulator SnTe upon impurity doping”, Nanoscale 14, 7151-7162 (2022). DOI: 10.1039/d1nr07120c
- A. Díaz-Fernández, F. Domínguez-Adame, Ó. de Abril, “Electron scattering by magnetic impurity in Weyl semimetals”, New. J. Phys. 23, 083003 (2021). DOI: 10.1088/1367-2630/ac14ce
Investigador DEFE: Óscar de Abril Torralba