Universality and the thermoelectric transport properties through a single electron transistor

International Conference and Exhibition on Mesoscopic & Condensed Matter Physics

June 22-24, 2015 Boston, USA

Roberto Franco Pe�±aloza

Colombia National University, Colombia

Posters-Accepted Abstracts: J Material Sci Eng

Abstract :

We discuss the temperature-dependent thermoelectric transport properties of semiconductor nanostructures comprising a quantum dot coupled to quantum wires, that is, the thermal dependence of the electrical conductance, thermal conductance, and thermo power. The physics of electrical and thermal conduction through the nanostructures is controlled by the antiferromagnetic interaction between the magnetic moment of the dot and the spins of the conduction electrons in the wires. At low temperatures, the conduction electrons tend to screen the dot moment, which gives rise to the Kondo effect. We explore the universality of the thermo-electric properties in the temperature range governed by the Kondo crossover. In this thermal range, general arguments indicate that the temperature dependence of any equilibrium property should be a universal function of the ratio T/TK, where TK is the Kondo temperature. Experimental work has nevertheless failed to identify universal behavior. On the theoretical front, the zero-bias electrical conductance through a quantum dot embedded in a quantum wire and the conductance through a quantum wire side-coupled to a quantum dot has recently been shown to map linearly onto the universal conductance for the particle-hole symmetric, spin-degenerate Anderson model. Here we extend this result to the other thermo-electric transport properties, the thermo power, and the thermal conductance. Our analysis relies on rigorous renormalization-group arguments. Illustrative numerical renormalization-group results are presented in order to illustrate the physics in our findings.

Biography :

Roberto Franco Peñaloza has completed his Bachelor and Master degree in Physics at the Universidad del Valle (Cali - Colombia), obtained his PhD in the Physics Institute of the Federal Fluminense Unversity from Niterói - Rio de Janeiro (Brazil) and did Postdoctoral studies at the Physics Department of the Catholic University of Rio de Janeiro. He is Associated Professor at the Physics Department of the Colombia National University - Bogotá, and has more of 50 publications in different International Journals about Condensed Matter Physics.

Email: rfrancop@unal.edu.co