Polarized hard X-ray photoemission system with micro-positioning technique for probing ground-state symmetry of strongly correlated materials

An angle-resolved linearly polarized hard X-ray photoemission spectroscopy (HAXPES) system has been developed to study the ground-state symmetry of strongly correlated materials. The linear polarization of the incoming X-ray beam is switched by a transmission-type phase retarder composed of two diamond (100) crystals. The best value of the degree of linear polarization was found to be −0.96, containing a 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 was 9 K, offering the chance to access the ground state even for strongly correlated electron systems in cubic symmetry. A co-axial sample monitoring system with long-working-distance microscope enables the same region on the sample surface to be measured before and after rotation. Combining this sample monitoring system with a micro-focused X-ray beam by means of an ellipsoidal Kirkpatrick–Baez mirror (25 µm × 25 µm FWHM), polarized valence-band HAXPES has been performed on NiO for voltage application as resistive random access memory to demonstrate the micro-positioning technique and polarization switching.

Source: Journal of Synchrotron Radiation - March 31, 2016 Category: Physics Authors: Fujiwara, H.Naimen, S.Higashiya, A.Kanai, Y.Yomosa, H.Yamagami, K.Kiss, T.Kadono, T.Imada, S.Yamasaki, A.Takase, K.Otsuka, S.Shimizu, T.Shingubara, S.Suga, S.Yabashi, M.Tamasaku, K.Ishikawa, T.Sekiyama, A. Tags: hard X-ray photoemission linear dichroism strongly correlated electron systems phase retarder micro-focused X-rays sample monitoring system low-temperature double-axis manipulator research papers Source Type: research