Studying the so-called ”hidden” phases of quantum materials—phases that do not exist under equilibrium conditions, but can be accessed with light—reveals new insights into the broader field of structural phase transitions. Using terahertz irradiation as well as hard x-ray probes made available by x-ray free electron lasers (XFELs) provides unique capabilities to study phonon dispersion in these materials. Here, we study the cubic peak of the quantum paraelectric strontium titanate (SrTiO3, STO) below the 110 K cubic-to-tetragonal tran- sition. Our results reveal a temperature and field strength dependence of the transverse acoustic mode in agreement with previous work on the avoided crossing occurring at finite wavevector, as well as evidence of anharmonic coupling between transverse optical phonons and a fully symmetric A1g phonon. These results elucidate previous optical studies on STO and hold promise for future studies on the hidden metastable phases of quantum materials.
In 1996, a floral and faunal inventory of the southeastern slopes of the Marojejy Massif, which falls in a protected area known as the Parc national de Marojejy, was conducted in an ascending series of altitudinal transect zones. The 1996 research team worked in five altitudinal zones (referred to as transect zones). Between 3 October and 15 November 2021, a floral and faunal inventory was completed, replicating the locations surveyed in 1996 and closely the dates. Detected bird species were analyzed for changes in elevational distribution between 1996 and 2021. Birds were divided into three feeding behavior groups and tolerance to forest habitat degradation was considered.