Strongly Disordered TiN and NbTiN s -Wave Superconductors Probed by Microwave Electrodynamics

作者：E. F. C. Driessen, P. C. J. J. Coumou, Rutger R. Tromp, Pieter de Visser, T. M. Klapwijk · 发表于：Physical Review Letters · 年份：2012 · DOI：10.1103/physrevlett.109.107003 · 被引用次数：143 · 研究领域：Physics of Superconductivity and Magnetism、Quantum and electron transport phenomena、Topological Materials and Phenomena

We probe the effects of strong disorder (2.4<k(F)l<8.6) on superconductivity in thin films of niobium titanium nitride and titanium nitride by measuring the microwave electrodynamics in coplanar waveguide resonators. We find a gradual evolution of the electromagnetic response with disorder, deviating from BCS theory, for both materials. This result can be understood as due to changes in the quasiparticle density of states, induced by the short elastic scattering length. The observations are consistent with a model using an effective pair breaker, dependent on the level of disorder.