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Volume 4, Issue 3(Suppl) J Laser Opt Photonics, an open access journal
ISSN: 2469-410X Quantum Physics 2017
September 25-26, 2017
September 25-26, 2017 Berlin, Germany
2nd International Conference on
Quantum Physics and
Quantum Technology
Experimental probing of quantum criticality at the superconductor-insulator quantum phase transition
Aviad Frydman
Bar Ilan University, Israel
The superconductor-insulator transition (SIT) is a prototype of a quantum phase transition which is very versatile experimentally:
varying a non-thermal tuning parameter such as disorder, thickness, composition, magnetic field or gate-voltage causes the
system to switch from a superconductor to an insulator at zero temperature. Unlike their classic counterparts, quantum phase
transitions are governed by quantum rather than thermal fluctuations at low temperatures. The direct experimental study of such
fluctuations close to the SIT is rather challenging. So far research has mainly concentrated on DC resistivity based measurements
such as transport and magnetoresistance and on global and local tunneling spectroscopy. These cannot provide explicit information
on the critical behavior through the transition. In my talk, I will describe two experimental efforts designed to measure signatures
of quantum fluctuations close to quantum criticality. The first experiment utilizes a unique, highly sensitive, setup to measure the
specific heat of ultrathin Pb films through the SIT. The specific heat is found to increase considerably as the sample is pushed towards
the SIT thus signaling quantum criticality. The second experiment is a scanning squid measurement able to probe local susceptibility
in TiNbN films close to the quantum transition. These studies reveal electronic superconducting granularity which fluctuates in time
and space at temperatures well below Tc. The temperature regime of these fluctuations grows as the SIT is approached indicating their
quantum nature. I will discuss the significance of these results and their contribution to understanding the electronic processes in the
vicinity of the quantum phase transition.
Biography
Aviad Frydman is an associate professor at the Department of Physics, Bar Ilan University, Israel. He completed his PhD for the thesis “Quantum Mechanical
Tunneling in the Presence of Intermediate States.” in the year 1996 from Hebrew University of Jerusalem.
Aviad Frydman, J Laser Opt Photonics 2017, 4:3(Suppl)
DOI: 10.4172/2469-410X-C1-014