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Published on: August 2, 2019
Universal Phonon-Mediated Superconductivity in Compressed Metal Monochalcogenides beyond Anderson Localization
Ertuğrul Karaca1,2, Fang Hong3,4, Daniel Errandonea5
1Sakarya University, Faculty of Sciences, Department of Physics, 54050, Sakarya, Turkey.
Physical Review Letters
|July 7, 2026
Summary
Superconductivity in metal monochalcogenides is driven by electron-phonon coupling, not disorder. Pressure decreases superconducting temperature, while decompression recovers intrinsic coupling in metastable phases.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Materials
Background:
- Superconductivity in metal monochalcogenides under pressure has been attributed to disorder-driven Anderson localization.
- Previous explanations for pressure-dependent superconductivity lacked a unified mechanism.
Purpose of the Study:
- To investigate the intrinsic mechanism governing superconductivity in metal monochalcogenides (BiSe, PbSe, PbS, HgS) under pressure.
- To resolve conflicting interpretations regarding the role of disorder and electron-phonon coupling.
Main Methods:
- Density-functional perturbation theory calculations.
- Migdal-Eliashberg theory for electron-phonon coupling analysis.
Main Results:
- Superconductivity is governed by a universal intrinsic electron-phonon coupling mechanism.
- Superconducting transition temperature (T_c) decreases monotonically with increasing pressure due to phonon hardening and reduced density of states.
- Observed T_c increases upon decompression result from the recovery of stronger coupling in metastable low-pressure phases.
Conclusions:
- A unified phonon-mediated description explains superconductivity in these metal monochalcogenides.
- Disorder and Anderson localization are not the primary drivers of superconductivity in these materials.
- The study resolves conflicting interpretations of experimental observations.
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