Photoemission System with Polarized Hard X-rays for Probing Ground State Symmetry of Strongly Correlated Materials
/ Authors
H. Fujiwara, S. Naimen, A. Higashiya, Y. Kanai, H. Yomosa, K. Yamagami, T. Kiss, T. Kadono, S. Imada, A. Yamasaki
and 9 more authors
K. Takase, S. Otsuka, T. Shimizu, S. Shingubara, S. Suga, M. Yabashi, K. Tamasaku, T. Ishikawa, A. Sekiyama
/ Abstract
We have developed a polarized hard X-ray photoemission (HAXPES) system to study the ground-state symmetry of strongly correlated materials. The linear polarization of the incoming X-ray beam is switched by the transmission-type phase retarder composed of two diamond (100) crystals. The best degree of the linear polarization $P_L$ is $-0.96$, containing the vertical polarization component of 98%. A newly developed low temperature two-axis manipulator enables easy polar and azimuthal rotations to select the detection direction of photoelectrons. The lowest temperature achieved is 9 K, offering us a chance to access the ground state even for the strongly correlated electron systems in cubic symmetry. The co-axial sample monitoring system with the long-working-distance microscope enables us to keep measuring the same region on the sample surface before and after rotation procedures. Combining this sample monitoring system with a micro-focused X-ray beam by means of an ellipsoidal Kirkpatrick-Baez mirror (25 $\mu$m $\times$ 25 $\mu$m (FWHM)), we have demonstrated the polarized valence-band HAXPES on NiO for voltage application as resistive random access memories to reveal the origin of the metallic spectral weight near the Fermi level.
Journal: arXiv: Strongly Correlated Electrons