Anisotropy in the thermal hysteresis of resistivity and charge density wave nature of single crystal SrFeO3-delta: X-ray absorption and photoemission studies

作者：Hsieh S H; Solanki R S; Wang Y F; Shao Y C; Lee S H; Yao C H; Du C H; Wang H T; Chiou J W; Chin Y Y; Tsai H M; Chen J L; Pao C W; Cheng C M; Chen W C; Lin H J; Lee J F; Chou F C; Pong W F^*

来源：Scientific Reports, 2017, 7(1): 161.

DOI：10.1038/s41598-017-00247-z

The local electronic and atomic structures of the high-quality single crystal of SrFeO3-delta (delta-0.19) were studied using temperature-dependent x-ray absorption and valence-band photoemission spectroscopy (VB-PES) to investigate the origin of anisotropic resistivity in the ab-plane and along the c-axis close to the region of thermal hysteresis (near temperature for susceptibility maximum, T-m similar to 78 K). All experiments herein were conducted during warming and cooling processes. The Fe L-3,L-2-edge X-ray linear dichroism results show that during cooling from room temperature to below the transition temperature, the unoccupied Fe 3d e(g) states remain in persistently out-of-plane 3d(3z) (2) (-r) (2) orbitals. In contrast, in the warming process below the transition temperature, they change from 3d(3z) (2) (-r) (2) to inplane 3d(x) (2) (-y) (2) orbitals. The nearest-neighbor (NN) Fe-O bond lengths also exhibit anisotropic behavior in the ab-plane and along the c-axis below T-m. The anisotropic NN Fe-O bond lengths and Debye-Waller factors stabilize the in-plane Fe 3d(x) (2) (-y) (2) and out-of-plane 3d(3z) (2) (-r) (2) orbitals during warming and cooling, respectively. Additionally, a VB-PES study further confirms that a relative band gap opens at low temperature in both the ab-plane and along the c-axis, providing the clear evidence of the chargedensity- wave nature of SrFeO3-delta (delta-0.19) single crystal.

• 出版日期2017-3-13
• 单位清华大学