Instability of the electric transport in superconductors

October 10, 2018

In a study published in Scientific Reports, researchers demonstrated that in two-dimensions the emergence of an instability is a hallmark of Berezinskii-Kosterlitz-Thouless transition they detected by transport measurements of titanium nitride films.

The I-V curves of TiN thin film at different temperatures. (a) The I-V curves shown in double logarithmic scale. Dotted line corresponds to α = 3 in V ∝ Iα dependence, dashed line corresponds to α = 1. Inset: temperature dependence of α exponent. Arrow marks the BKT transition temperature defined from the condition α = 3, TBKT≃3.03 K. (b) The I-V curves are shown in the linear scale. Solid lines are the theoretical curves according to Eqs (22, 23). Arrows mark the direction of the voltage jump: with the current increasing from zero–jump up; with the current decreasing to zero–jump down. Inset: The temperature dependence of the fitting parameter ω. At T≃TBKT parameter ω reaches the maximum.

Scientific Achievement

We develop a theory of inherent non-thermal superconducting electronic instabilities.

Significance and Impact

Our result provides key insights into the origin of switching voltage instabilities in superconductors.

Research Details

A theory is constructed in the framework of the time-dependent Ginzburg-Landau equation.
The S-shape of the I-V curves is generated by superconducting fluctuations.
In 2D superconductors, the Berezinskii-Kosterlitz-Thouless transition is accompanied – and can be identified – by the voltage switching jumps.

DOI: 10.1038/s41598-018-32302-8

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