Phys.org February 7, 2022
Hysteresis underlies many phase transitions in solids, giving rise to exotic metastable states that are otherwise inaccessible. An international team of researchers (USA – MIT, UC Berkeley, Stanford University, SLAC Linear Accelerator Laboratory, Cornell University, Argonne National Laboratory, Clemson University, China, Russia, Germany) reported an unconventional hysteretic transition in a quasi-2D material, EuTe4. They observed that the hysteresis loop has a temperature width of more than 400 K, setting a record among crystalline solids. The transition has an origin distinct from known mechanisms, lying entirely within the incommensurate charge density wave (CDW) phase of EuTe4 with no change in the CDW modulation periodicity. They interpreted the hysteresis as an unusual switching of the relative CDW phases in different layers, a phenomenon unique to quasi-2D compounds that is not present in either purely 2D or strongly coupled 3D systems. Their findings challenge the established theories on metastable states in density wave systems. In future research they plan to trick EuTe4 into a different resistive state after shining a single flash of light, making it an ultrafast electrical switch that can be used, for instance, in computing devices…read more. TECHNICAL ARTICLE
A cartoon illustrates a hysteresis with different uphill and downhill paths. Credit: Xinyue Lu