Science Daily April 12, 2022
A key to unlocking new functionalities in quantum materials is the discovery of tunable coupling between spins and other microscopic degrees of freedom. A team of researchers in the US (Pennsylvania State University, University, UC San Diego, Northwestern University SLAC National Accelerator Laboratory, Argonne National Laboratory, Stanford University) has found evidence for interlayer magnetophononic coupling in the layered magnetic topological insulator MnBi2Te4. They observed anomalies in phonon scattering intensities across magnetic field-driven phase transitions, despite the absence of discernible static structural changes. This behavior is a consequence of a magnetophononic wave-mixing process that allows for the excitation of zone-boundary phonons that are otherwise ‘forbidden’ by momentum conservation. Their calculations revealed that this phenomenon can be attributed to phonons modulating the interlayer exchange coupling. According to the researchers the magnetophononic coupling represents an important step towards coherent on-demand manipulation of magnetic topological phases…read more. Open Access TECHNICAL ARTICLE
Phonon anomalies across magnetic phase transitions in MnBi2Te4. Credit: Nature Communications volume 13, Article number: 1929 (2022)