Revealing the structural distortion of rare-earth Gd at low temperature

Our lab. XRD indicates that rare earth Gd metal undergoes slightly Bragg peak broadening at low temperature, indicating a possible new phase at low temperature that has not been reported before. Our first-principles many-body calculations for the correlated 4f-shell of Gd predict that an orthorhombic phase could be stabilized by magneto-elastic forces due to ordering of Gd quadrupolar moments. Further high-resolution synchrotron XRD at ID22 is highly preferred to directly characterize the low-temperature structural distortion and reveal the low-symmetric structure. The determination of the true structure of pure Gd metal is important to further understand the nature of rare earth, such as electron structure, energy bands, phonons, and magnetism.