Crystal and Electronic Structure of FeSe at High Pressure and Low Temperature

详细信息    查看全文

• 作者：Ravhi S. Kumar ; Yi Zhang ; Stanislav Sinogeikin ; Yuming Xiao ; Sathish Kumar ; Paul Chow ; Andrew L. Cornelius ; Changfeng Chen
• 刊名：Journal of Physical Chemistry B
• 出版年：2010
• 出版时间：October 7, 2010
• 年：2010
• 卷：114
• 期：39
• 页码：12597-12606
• 全文大小：444K
• 年卷期：v.114,no.39(October 7, 2010)
• ISSN：1520-5207

文摘

We have investigated the high-pressure crystal and electronic structures of superconducting FeSe by high-resolution synchrotron powder X-ray diffraction and density functional theory (DFT) calculations at ambient and at low temperatures down to 8 K. Ambient nuclear resonant inelastic X-ray scattering (NRIXS) experiments were performed on FeSe to understand the partial phonon density of states (PDOS) of the high-pressure phases. On the basis of our experimental results and DFT calculations, we demonstrate a pressure-induced distortion of the low-temperature Cmma phase at around 1.6 GPa and the appearance of a high-pressure Pbnm phase. Upon increasing the pressure above 9 GPa, the orthorhombic phase becomes the major phase, and a mixed-phase region exists up to 26 GPa. The pressure-induced structural changes in this system and its connection to T_c enhancement are discussed.