Thickness-tuned superconductor–insulator transitions in quench-condensed Mo and MoRu films

Abstract

The results of studies on superconductor-insulator transitions are reported for Mo and MoRu films of varying thickness deposited on SiO underlayers and on bare glass. The film samples were quench-condensed on glass substrates held at liquid He temperatures. MoRu films on SiO, which offer the most homogeneous film morphology, showed a critical sheet resistance of transition, R c , of ∼6.7 k . Both series of Mo films on SiO and MoRu films on bare glass had R c 13 k . These values are larger than those previously reported for MoGe, MoSi, and MoC films. For the above films in the insulating region far from the transition, the exponent of the thermally activated resistance ranged from 0.5 to 1.0.

Enhanced superconductivity and superconductor to insulator transition in nano-crystalline molybdenum thin films

“…There are few reports of enhancement of TC in thin amorphous films of Mo deposited at liquid helium temperature [31] but here we report disorder induced SIT via intermediary metallic phase in molybdenum thin films, sputter deposited at room temperature under varying argon pressure. In addition to transition into insulating state, our nano-crystalline thin films show enhancement in TC as reported in amorphous Mo films [24].…”

Enhanced suppression of superconductivity in amorphous films with nano-scale patterning

“…Those factors which produce this steady reduction in the superconducting critical temperature, T c , have been considered by many. Good fits can be achieved to various theories that attribute the T c reduction to enhancements in electron-electron interactions [7][8][9][10][11][12]. However, few experimental tests of the robustness of these theories against the presence of nano-variations in either the film thickness or film structure have been undertaken.…”

Superconductivity in two-dimensional η-Mo3C2 films

“…After fabricating standard four-probe contacts, we measured the temperature-dependent resistances of these grown η-Mo 3 C 2 films with different thicknesses. Moreover, amorphous molybdenum films are reported to present superconducting characteristic [31], so we firstly confirm the temperature dependence of the resistance of the as-sputtered 3.6-nm-thick molybdenum film. In Fig.…”