Department of Physics, University of Alabama at Birmingham (UAB), Birmingham, AL 35294, USA.
J Phys Condens Matter. 2012 Sep 12;24(36):362201. doi: 10.1088/0953-8984/24/36/362201. Epub 2012 Aug 15.
X-ray diffraction studies were carried out on the rare earth metal yttrium up to 177 GPa in a diamond anvil cell at room temperature. Yttrium was compressed to 37% of its initial volume at the highest pressure. The rare earth crystal structure sequence hcp → Sm type → dhcp → mixed(dhcp + fcc) → distorted fcc (dfcc) is observed in yttrium below 50 GPa. The dfcc (hR24) phase has been observed to persist in the pressure range of 50-95 GPa. A structural transition from dfcc to a low symmetry phase has been observed in yttrium at 99 ± 4 GPa with a volume change of - 2.6%. This low symmetry phase has been identified as a monoclinic C2/m phase, which has also been observed in other rare earth elements under high pressures. The appearance of this low symmetry monoclinic phase in yttrium shows that its electronic structure under extreme conditions resembles that of heavy rare earth metals, with a significant increase in d-band character of the valence electrons and possibly some f-electron states near the Fermi level.
室温条件下，在金刚石对顶砧高压腔中对稀土金属钇进行了高达 177GPa 的 X 射线衍射研究。在最高压力下，钇被压缩到初始体积的 37%。在 50GPa 以下的钇中，观察到了稀土晶体结构序列 hcp→Sm 型→dhcp→混合（dhcp+fcc）→扭曲 fcc（dfcc）。dfcc（hR24）相在 50-95GPa 的压力范围内一直存在。在 99±4GPa 时，观察到钇从 dfcc 向低对称性相的结构转变，体积变化为-2.6%。这种低对称性相被确定为单斜 C2/m 相，在高压下也在其他稀土元素中观察到。这种低对称性单斜相在钇中的出现表明，其在极端条件下的电子结构类似于重稀土金属，价电子的 d 带特征显著增加，费米能级附近可能有一些 f 电子态。
