Strain effects in monolayer Iron-Chalcogenide superconductors

TL;DR

This study investigates how tensile strain influences the magnetic and electronic properties of monolayer and bulk FeSe and FeTe, revealing phase transitions and potential for substrate growth in high-temperature superconductors.

Contribution

It provides new insights into strain-induced magnetic phase transitions in monolayer and bulk iron-chalcogenide superconductors, expanding understanding of their tunable properties.

Findings

Tensile strain induces magnetic phase transitions in FeSe and FeTe.

Monolayer FeSe's magnetic ground state shifts under strain.

FeTe exhibits multiple magnetic transitions with increasing strain.

Abstract

The successful fabrication of one monolayer FeSe on SrTiO$_{3}$ represented a real breakthrough in searching for high-T$_{c}$ Fe-based superconductors (Ref. 1). Motivated by this important discovery, we studied the effects of tensile strain on one monolayer and bulk iron-chalcogenide superconductors (FeSe and FeTe), showing that it produces important magnetic and electronic changes in the systems. We found that the magnetic ground state of bulk and monolayer FeSe is the block-checkerboard phase, which turns into the collinear stripe phase under in plane tensile strain. FeTe, in both bulk and monolayer phases, shows two magnetic transitions upon increasing the tensile strain: from bicollinear in the ground state to block-checkerboard ending up to the collinear antiferromagnetic phase which could bring it in the superconducting state. Finally, the study of the mechanical properties of both FeSe and FeTe monolayers reveals their enormous tensile strain limits and opens the possibility to grow them on different substrates.