Spin-Orbit Coupling Effect over Kondo Temperature and Thermoelectric Transport Properties of a Quantum Dot

• Autor: Manya Suni, Marco Antonio
• Formato: tesis doctoral
• Fecha de Publicación: 2021
• Institución: Superintendencia Nacional de Educación Superior Universitaria
• Repositorio: Registro Nacional de Trabajos conducentes a Grados y Títulos - RENATI
• Lenguaje: inglés
• OAI Identifier: oai:repositorio.sunedu.gob.pe:20.500.14366/398
• Enlace del recurso: https://hdl.handle.net/20.500.14366/398
• Nivel de acceso: acceso abierto
• Materia: Acoplamiento espín-órbita; Efecto Kondo; Ley de Wiedemann-Franz; Puntos cuánticos; https://purl.org/pe-repo/ocde/ford#1.03.01

This thesis presents the research results of a quantum dot coupled to a conduction band with spin-orbit coupling (SOC), Specifically, a simgle electron transistor (SET). We study the dependence of the Kondo temperature and the thermoelectric transport properties with SOC. The problem is modeled as a single impurity Anderson model in the presence of the conduction band spin-orbit interaction. The SOC mixes the spins of the conducting electrons, and as a consequence, the SU(2) spin symmetry of the Anderson Hamiltonian is broken. We recover the Anderson Hamiltonian SU(2) symmetry through a rotation of the system’s spins along with rˆ axis, where the ground state of the problem can be considered the Kondo many-body singlet state. On this quantization axis, the Anderson Hamiltonian can be rewritten in the same way as the original Anderson Hamiltonian, with which we obtain a continuous density of states of the conduction band, a diagonal hybridization function on the spin rotated basis, and that the Haldane formula for the Kondo temperature can be rewritten, renormalized by the conduction band SOC. In the study of thermoelectric transport properties, we observe that in both: the atomic and the numerical renormalization group (NRG) methods, the Kondo temperature decreases with the increasing of the SOC. It is because the Friedel sum rule is satisfied under conduction band SOC. In the transport properties, we obtain that the electrical, thermal conductance, and thermopower exhibit universality in the presence of spin-orbit coupling. Similarly, we observe the violation of the Wiedemann-Franz law, and the figure of merit ZT increases with the presence of de conduction band SOC. In short, the SOC interaction drives the system to the Kondo regime.