Dimension Effects in Insulating NbTiN Disordered Films and the Asymptotic Freedom of Cooper Pairs

JETP Letters - We investigate the evolution of the electronic transport in disordered NbTiN films at the insulating side of the superconductor-insulator transition as function of the effective...     

Magnetic Field Evolution of the Linear and Nonlinear Conduction of Perforated TiN Films

Journal of Experimental and Theoretical Physics - The low-temperature linear and nonlinear transport on nanoperforated titanium nitride films is experimentally studied. A metallic Bose state is...     

Superconducting properties of long TiN wires

The low-temperature transport properties of titanium nitride wires with the width comparable with or much larger than the superconducting coherence length are studied experimentally. It is shown that the reduction of the width of wires does not affect the transport properties at the temperatures above the superconducting transition temperature and electron transport in this temperature range is determined by quantum contributions to the conductivity from weak localization and electron–electron interaction. It is established that the reduction of the width of wires does not change the superconducting transition temperature but completely suppresses the topological Berezinskii–Kosterlitz–Thouless transition. It is found that the threshold magnetic field increases with a decrease in the width of wires.     

Superconductor–Insulator Transition in NbTiN Films

Experimental results indicating a direct disorder-induced superconductor–insulator transition in NbTiN thin films have been reported. It has been shown that an increase in the resistance per square in the normal state is accompanied by the suppression of the critical temperature of the superconducting transition T_c according to the fermion mechanism of suppression of superconductivity by disorder. At the same time, the temperature of the Berezinskii–Kosterlitz–Thouless transition is completely suppressed at a nonzero critical temperature and, then, the ground state changes to insulating, which is characteristic of the boson model of suppression of superconductivity by disorder. It has been shown that the temperature dependences of the resistance of insulating films follow the Arrhenius activation law.