Parity-violating current-voltage curves in a single domain of superconductors
Introduction
Anisotropic superconductors [1], [2], [3] stimulate much interest in a nontrivial order parameter field. Since the internal degrees of freedom of the order parameter provide domain configurations, the experimental data of millimeter-scale superconductors could be considered as a result of ensemble-averaging over domain configurations. crystals form domains with different chirality by the angular momentum of Cooper pairs [2]. The size of a single chiral order parameter domain is suggested to be . Thus, it is important to extract peculiar effects by measuring the only single domain. However, transport measurements of the single domain are still limited [4].
Section snippets
Experiment
crystals were grown with a solid-phase reaction. The samples were dispersed in dichloroethane by sonication and deposited on an oxidized Si substrate. We selected microscale single crystals from the chemical composition and crystallinity. We confirmed that the dispersed crystals had no boundaries nor ruthenium inclusions on the surface by observing the crystal orientation using the electron backscatter diffraction pattern. On the analyzed samples, we fabricated gold electrodes
Result and discussion
We observed anomalous the I–V curves in zero magnetic field. Fig. 1(b) shows I–V curves at temperatures with typical flat tail resistances of . The transition temperature is 1.69 K. Finite resistivity shows the flow of vortices due to quantum fluctuations of the phase. In general, the voltage in I–V curves for metals, quantum Hall systems and Josephson junction is always odd function of bias current (i.e., change signs under the space inversion), which is a result of parity
Summary
We studied the transport properties in a chiral single domain of microscale single crystals. single crystals were selected by detailed analyses. Gold electrodes were attached durably by welding with electron beam irradiation. The parity-violating I–V curves were observed.
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