marzo 4, 2020

Lic. Mariano Real (English Version)

( Instituto Nacional de Tecnología Industrial )

Topic: Thermoelectric effects in 2D systems in the quantum Hall state.

The quantum Hall effect is a characteristic of 2D systems (2DES), its impact in solid-state physics is profound and has even influenced our everyday life, today the national standard of resistance is based on the quantum Hall state of GaAs/AlGaAs devices.
For some years now, great attention to thermoelectric mechanisms have emerged with proposals to be implemented as thermoelectric cooling systems. Several works have studied the thermoelectric properties of these systems in the so-called Hall bar configuration, having the disadvantage that the effect is naturally mixed between the tensor components (Onsager). I will present studies produced in Corbino structures, where this mixing is naturally absent. A central heater allows us to produce a thermal gradient along the sample radius inducing the desired thermoelectric effects.
I will present experimental results and its theoretical modeling, where we were able to study the electronic contribution to the transport properties of the system. Also, thermal gradient estimations and its effect in the thermoelectric response will be presented, both theoretically and experimentally.
Our findings indicate a high thermoelectric performance of the system, indicating that technological applications in low-temperature systems could be produced, this is cooling devices and temperature sensors.

Summary Background

Mariano received his Lic. in Physics degree from Universidad de Buenos Aires. He received a scholarship from Instituto Nacional de Tecnología Industrial (INTI), where he now develops his work in the Quantum Metrology Division. Along his colleges he maintain and develop the national standard of resistance, based in the quantum Hall effect (QHE).
As a guest researcher, he collaborated in a project with NIST (metrology institute USA) to study the growth process, post-processing and development of an epitaxial graphene-based resistance standard. Afterward, he collaborated as a guest researcher at PTB (metrology institute Germany)  to develop and study the QHE in GaAs/AlGaAs. He is currently studying transport and thermoelectric properties of such systems in a collaboration between INTI, ICAS-UNSAM, INN-CNEA, ETH (Switzerland) and MPI (Germany).
Given his usual work at INTI he specialized in high precision resistance measurements, particularly in high current systems, and also in high precision magnetotransport measurements.