Person: Baba, Yuriko Caterina
Loading...
First Name
Yuriko Caterina
Last Name
Baba
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
Department
Física de Materiales
Area
Identifiers
5 results
Search Results
Now showing 1 - 5 of 5
Item Many-impurity scattering on the surface of a topological insulator(Scientific reports, 2021) Hernando Grande, Antonio; Baba, Yuriko Caterina; Díaz García, Elena; Domínguez-Adame Acosta, FranciscoWe theoretically address the impact of a random distribution of non-magnetic impurities on the electron states formed at the surface of a topological insulator. The interaction of electrons with the impurities is accounted for by a separable pseudo-potential method that allows us to obtain closed expressions for the density of states. Spectral properties of surface states are assessed by means of the Green's function averaged over disorder realisations. For comparison purposes, the configurationally averaged Green's function is calculated by means of two different self-consistent methods, namely the self-consistent Born approximation (SCBA) and the coherent potential approximation (CPA). The latter is often regarded as the best single-site theory for the study of the spectral properties of disordered systems. However, although a large number of works employ the SCBA for the analysis of many-impurity scattering on the surface of a topological insulator, CPA studies of the same problem are scarce in the literature. In this work, we find that the SCBA overestimates the impact of the random distribution of impurities on the spectral properties of surface states compared to the CPA predictions. The difference is more pronounced when increasing the magnitude of the disorder.Item Rashba coupling and spin switching through surface states of Dirac semimetals(New journal of physics, 2021) Baba, Yuriko Caterina; Domínguez-Adame Acosta, Francisco; Platero, Gloria; Molina, Rafael A.We study the effect of the Rashba spin-orbit coupling on the Fermi arcs of topological Dirac semimetals. The Rashba coupling is induced by breaking the inversion symmetry at the surface. Remarkably, this coupling could be enhanced by the interaction with the substrate and controlled by an external electric field. We study analytically and numerically the rotation of the spin of the surface states as a function of the electron's momentum and the coupling strength. Furthermore, a detailed analysis of the spin-dependent two-terminal conductance is presented in the clean limit and with the addition of a random distribution of impurities. Depending on the magnitude of the quadratic terms in the Hamiltonian, the spin-flip conductance may become dominant, thus showing the potential of the system for spintronic applications, since the effect is robust even in the presence of disorder.Item Effect of external fields in high Chern number quantum anomalous Hall insulators(Physical review B, 2022) Baba, Yuriko Caterina; Amado, Mario; Díez, Enrique; Domínguez-Adame Acosta, Francisco; Molina, Rafael A.A quantum anomalous Hall state with a high Chern number has so far been realized in multilayer structures consisting of alternating magnetic and undoped topological insulator (TI) layers. However, in previous proposals, the Chern number can only be tuned by varying the doping concentration or the width of the magnetic TI layers. This drawback largely restricts the applications of dissipationless chiral edge currents in electronics since the number of conducting channels remains fixed. In this paper, we propose a way of varying the Chern number at will in these multilayered structures by means of an external electric field applied along the stacking direction. In the presence of an electric field in the stacking direction, the inverted bands of the unbiased structure coalesce and hybridize, generating new inverted bands and collapsing the previously inverted ones. In this way, the number of Chern states can be tuned externally in the sample, without the need for modifying the number and width of the layers or the doping level. We showed that this effect can be uncovered by the variation of the transverse conductance as a function of the electric field at constant injection energy at the Fermi level.Item Impact of electron-electron interactions on the thermoelectric efficiency of graphene quantum point contacts(Physical review B, 2022) Sánchez Ramírez, Irián; Baba, Yuriko Caterina; Chico Gómez, Leonor; Domínguez-Adame Acosta, FranciscoThermoelectric materials enable us to harness dissipated energy and make electronic devices less energydemanding. Heat-to-electricity conversion requires materials with a strongly suppressed thermal conductivity but still high electronic conduction. This goal is largely achieved with the help of nanostructured materials, even if the bulk counterpart is not highly efficient. In this work, we investigate how thermoelectric efficiency is enhanced by many-body effects in graphene nanoribbons at low temperature. To this end, starting from the Kane-Mele-Hubbard model within a mean-field approximation, we carry out an extensive numerical study of the impact of electron-electron interactions on the thermoelectric efficiency of graphene nanoribbons with armchair or zigzag edges. We consider two different regimes, namely trivial and topological insulators. We find that electron-electron interactions are crucial for the appearance of interference phenomena that give rise to an enhancement of the thermoelectric efficiency of the nanoribbons. Lastly, we also propose an experimental setup that would help to test the validity of our conclusions.Item Correction: persistence of symmetry-protected Dirac points at the surface of the topological crystalline insulator SnTe upon impurity doping(Nanoscale, 2023) Arroyo Gascón, Olga; Baba, Yuriko Caterina; Cerdá, Jorge I.; Abril, Óscar de; Martínez Casado, Ruth; Domínguez-Adame Acosta, Francisco; Chico Gómez, Leonor