Two‑Dimensional Superconductors

Superconductivity was among the properties of graphene, the 2D wonder material opening the way for superconducting device and quantum memory qubits. Nowadays, other 2D materials reach much higher superconducting temperatures. 2D materials (Janus chalcogenides, boride monolayers, MXenes) can host phonon‑mediated superconductivity at remarkable temperatures for atomically thin systems. They are grown experimentally with chemical vapour deposition, but this is challenging and calculations are the best way to determine what might be worth making.

structure
2D materials are in fact trilayers, typically with light elements like sulphur and hydrogen top and bottom, and heavy metals like molybdenum in the middle.
strain and holes
Calculation of superconductivity uses Eliashberg theory: first we calculate which electrons can move easily (the "Fermi surface", then we calculate if vibrations of the atoms can pair up these electrons so they move together and cannot be scattered: this is superconductivity.

References

  1. Seeyangnok, Hassan, Pinsook & Ackland, Superconductivity and electron self-energy in tungsten–sulfur–hydride monolayer, 2D Materials (2024)
  2. Seeyangnok, Pinsook & Ackland, High-Tc 2D ambient BCS superconductors in hydrogenated transition-metal borides, npj 2D Materials and Applications (2025)
  3. Seeyangnok, Pinsook, Ackland, Competition between superconductivity and ferromagnetism in 2d janus mxH (m= Ti, Zr, Hf, x= S, Se, Se) monolayer Journal of Alloys and Compounds 1033, 180900
  4. Seeyangnok Pinsook, Ackland Superconductivity and strain-enhanced phase stability of Janus tungsten chalcogenide hydride monolayers, Seeyangnok, Pinsook, Ackland (2024) Physical Review B