Disorder-broadened phase boundary with enhanced amorphous superconductivity in pressurized In2Te5

TL;DR

This study reveals a disorder-broadened phase boundary in pressurized In2Te5, where amorphous regions exhibit enhanced superconductivity due to increased electron correlation, expanding understanding of phase transitions and superconductivity.

Contribution

It introduces a new amorphous transition region in the phase diagram of In2Te5 and links disorder-induced amorphous phases to enhanced superconductivity with a theoretical explanation.

Findings

Amorphous phase shows 25% higher Tc than crystalline phases.

Disorder broadens the phase boundary from a sharp to a transition region.

Enhanced electron correlation may cause increased superconductivity in amorphous regions.

Abstract

As an empirical tool in materials science and engineering, the iconic phase diagram owes its robustness and practicality to the topological characteristics rooted in the celebrated Gibbs phase law (F = C - P + 2). When crossing the phase diagram boundary, the structure transition occurs abruptly, bringing about an instantaneous change in physical properties and limited controllability on the boundaries (F = 1). Here, we expand the sharp phase boundary to an amorphous transition region (F = 2) by partially disrupting the long-range translational symmetry, leading to a sequential crystalline-amorphous-crystalline (CAC) transition in a pressurized In2Te5 single crystal. Through detailed in-situ synchrotron diffraction, we elucidate that the phase transition stems from the rotation of immobile blocks [In2Te2]2+, linked by hinge-like [Te3]2- trimers. Remarkably, within the amorphous region, the amorphous phase demonstrates a notable 25 % increase of the superconducting transition temperature (Tc), while the carrier concentration remains relatively constant. Furthermore, we propose a theoretical framework revealing that the unconventional boost in amorphous superconductivity might be attributed to an intensified electron correlation, triggered by a disorder-augmented multifractal behavior. These findings underscore the potential of disorder and prompt further exploration of unforeseen phenomena on the phase boundaries.