Mironov A Yu, Silevitch D M, Postolova S V, Burdastyh M V, Proslier T, Baturina T I, Rosenbaum T F, Vinokur V M
Rzhanov Institute of Semiconductor Physics SB RAS, 13 Lavrentjev Avenue, Novosibirsk, Russia, 630090.
Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA, 91125, USA.
Sci Rep. 2021 Aug 10;11(1):16181. doi: 10.1038/s41598-021-95530-5.
We investigate the low-temperature complex impedance of disordered insulating thin TiN and NbTiN films in the frequency region 400 Hz-1 MHz in close proximity to the superconductor-insulator transition (SIT). The frequency, temperature, and magnetic field dependencies of the real and imaginary parts of the impedance indicate that in full accord with the theoretical predictions and earlier observations, the films acquire self-induced electronic granularity and become effectively random arrays of superconducting granules coupled via Josephson links. Accordingly, the inductive component of the response is due to superconducting droplets, while the capacitive component results from the effective Josephson junctions capacitances. The impedance crosses over from capacitive to inductive behavior as films go across the transition.
我们研究了无序绝缘薄TiN和NbTiN薄膜在接近超导体-绝缘体转变（SIT）的400 Hz - 1 MHz频率范围内的低温复阻抗。阻抗实部和虚部的频率、温度及磁场依赖性表明，与理论预测和早期观察结果完全一致，这些薄膜获得了自感应电子粒度，并成为通过约瑟夫森结耦合的有效超导颗粒随机阵列。因此，响应的电感分量归因于超导微滴，而电容分量则源于有效约瑟夫森结电容。当薄膜越过转变点时，阻抗从电容性行为转变为电感性行为。
