Emergent tetragonality in a fundamentally orthorhombic material.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38781340.
- Also identified by DOI 10.1126/sciadv.adk3321 and PMC identifier 11114214.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Symmetry plays a key role in determining the physical properties of materials. By Neumann's principle, the properties of a material remain invariant under the symmetry operations of the space group to which the material belongs. Continuous phase transitions are associated with a spontaneous reduction in symmetry. Less common are examples where proximity to a continuous phase transition leads to an increase in symmetry. We find signatures of an emergent tetragonal symmetry close to a charge density wave (CDW) bicritical point in a fundamentally orthorhombic material, ErTe<sub>3</sub>, for which the two distinct CDW phase transitions are tuned via anisotropic strain. We first establish that tension along the <i>a</i> axis favors an abrupt rotation of the CDW wave vector from the <i>c</i> to <i>a</i> axis and infer the presence of a bicritical point where the two continuous phase transitions meet. We then observe a divergence of the nematic elastoresistivity approaching this putative bicritical point, indicating an emergent tetragonality in the critical behavior.