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Spin-orbit interaction in semiconductor nanostructures and topological insulators

Grant number: 16/03854-9
Support type:Regular Research Grants
Duration: August 01, 2016 - September 30, 2018
Field of knowledge:Physical Sciences and Mathematics - Physics
Principal Investigator:Erasmo Assumpção de Andrada e Silva
Grantee:Erasmo Assumpção de Andrada e Silva
Home Institution: Instituto Nacional de Pesquisas Espaciais (INPE). Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brasil). São José dos Campos , SP, Brazil
Assoc. researchers: Marcelo Alejandro Toloza Sandoval

Abstract

The spin-orbit interaction (SO) in semiconductors and semiconductor nanostructures is responsible for purely quantum mechanical properties of great technological interest, such as the Rashba effect and the polarized states on the surface (or edge) of topological insulating structures and materials. These properties form the basis of several proposals of new spintronic devices and today attract much attention from the scientific community, in the search for a comprehensive understanding of the effects of SO interaction in semiconductor materials and structures with different topologies. Among the open problems today, we highlight the effects of the g-factor (one of the key parameters in spintronics engineering) renormalization in nanostructures, as well as the electronic structure of the surface states of different III-V and IV-VI nanostructures, which is characteristic of the topological insulators; both effects are determined in first order by the Rashba term of the SO interaction, which is well described by multi- bands kp models in the envelope function approximation. This project proposes a theoretical study with the overall goal of developing the physics SO interaction in semiconductor nanostructures, guided by these two problems. Following a traditional and very useful methodology in semiconductor physics, we start from an analytical model for the volumetric semiconductor (multi-band kp models, ie Kane for III-V and Dimmock for IV-VI), derive effective Hamiltonians for electrons in different nanostructures and external applied field configurations, solve the electronic structure, calculate different properties and analyze the results with the experimental data. The main applications (or specific objectives) of the theory are: 1. Calculation and study of the polarized states at IV-VI (PbTe / PbSnTe) inverted gap interfaces (single and interacting) and in the edges of III-V (GaSb / InAs) quantum wires with topological properties; and 2) Calculation of the g-factor renormalization in general III-V and IV-VI quantum wells (i.e. asymmetric, double symmetric and asymmetric etc), superlattices and quantum wires. Among the expected results to be presented at major conferences of the area and published in international journals, there is the derivation of general analytical expressions for determining the g-factor in nanostructures and the electronic structure of polarized states ("helical / protected") at the surface or edges of semiconductor nanostructures with nontrivial topology. (AU)

Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
LEON PADILLA, JHON ELBER; TOLOZA SANDOVAL, MARCELO ALEJANDRO; DA SILVA, ANTONIO FERREIRA; DE ANDRADA E SILVA, ERASMO ASSUMPCAO; LA ROCCA, GIUSEPPE CARLO. g-Factor Anisotropy Inversion in InGaAs 2D Nanostructures. PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, v. 256, n. 6, SI JUN 2019. Web of Science Citations: 0.
TOLOZA SANDOVAL, M. A.; LEON PADILLA, J. E.; FERREIRA DA SILVA, A.; DE ANDRADA E SILVA, E. A.; LA ROCCA, G. C. Mesoscopic g-factor renormalization for electrons in III-V interacting nanolayers. Physical Review B, v. 98, n. 7 AUG 28 2018. Web of Science Citations: 0.

Please report errors in scientific publications list by writing to: cdi@fapesp.br.
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