Superconducting order from disorder in 2H-TaSe 2− x S x

Abstract

Condensed matter physics: crystallographic disorder enhances superconductivity Substituting sulfur into TaSe2 induces disorder, which further helps to enhance superconductivity, with a higher transition temperature. It is higher than that of either TaSe2 or TaS2. An international team of researchers led by Cedomir Petrovic at Brookhaven national laboratory of USA synthesized single crystal alloys of TaSe2− x S x and measured the electrical conductivity and superconducting transition temperature as a function of x. They found that the transition temperature optimally increased when a maximal disorder is introduced by substituting sulfur into TaSe2. The role of such a disorder was understood as to suppress other competing orders while keeping superconductivity intact. By breaking other orders, conducting carriers were released so that they contributed further to superconductivity. These results highlight a benefit role of disorder and provide a possible way to enhance superconductivity.