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Quantum criticality at the superconductor to insulator transition revealed by specific heat measurements

Quantum criticality at the superconductor to insulator transition revealed by specific heat measurements

Authors :
Poran, Shachaf
Nguyen-Duc, Tuyen
Auerbach, Assa
Dupuis, Nicolas
Frydman, Aviad
Bourgeois, Olivier
Source :
Nature Communications, 8, 14464, (2017)
Publication Year :
2017

Abstract

The superconductor-insulator transition (SIT) is considered an excellent example of a quantum phase transition which is driven by quantum fluctuations at zero temperature. The quantum critical point is characterized by a diverging correlation length and a vanishing energy scale. Low energy fluctuations near quantum criticality may be experimentally detected by specific heat, $c_{\rm p}$, measurements. Here, we use a unique highly sensitive experiment to measure $c_{\rm p}$ of two-dimensional granular Pb films through the SIT. The specific heat shows the usual jump at the mean field superconducting transition temperature $T_{\rm c}^{\rm {mf}}$ marking the onset of Cooper pairs formation. As the film thickness is tuned toward the SIT, $T_{\rm c}^{\rm {mf}}$ is relatively unchanged, while the magnitude of the jump and low temperature specific heat increase significantly. This behaviour is taken as the thermodynamic fingerprint of quantum criticality in the vicinity of a quantum phase transition.<br />Comment: 9 pages, 5 figures, 1 table

Details

Database :
arXiv
Journal :
Nature Communications, 8, 14464, (2017)
Publication Type :
Report
Accession number :
edsarx.1703.07954
Document Type :
Working Paper
Full Text :
https://doi.org/10.1038/ncomms14464