主催: The Japan Society of Vacuum and Surface Science
会議名: 2023年日本表面真空学会学術講演会
開催地: 名古屋
開催日: 2023/10/31 - 2023/11/02
Photoelectron momentum microscope (PMM) is an instrument built on a new concept based on imaging-type photoelectron spectroscopy and microscopy techniques to visualize the electronic state in k reciprocal lattice space of a selected microscopic region [1]. We constructed a PMM station at the soft X-ray undulator beamline BL6U [2-4] of UVSOR synchrotron facility [5]. PMM offers a new approach for μm-scale momentum-resolved photoelectron spectroscopy (MRPES) [6-12]. A key feature of the PMM is that it can very effectively reduce radiation-induced damage by directly projecting a single photoelectron constant energy contour in reciprocal space with a radius of a few Å-1 or real space with a radius of a few hundred μm onto a two-dimensional detector. This approach was applied to three-dimensional valence band structure E(k) and E(r) measurements (stereography) as functions of photon energy (hν), its polarization (e), detection position (r), and temperature (T). In this presentation, we describe some examples of possible measurement techniques using UVSOR PMM.
We are taking a new step forward from the conventional framework of studying electronic properties of various materials by means of μm-scale valence band mapping and momentum-selective photoelectron microscopy [4,9,12]. With a hν range up to 800 eV covered by the BL6U, core-level excitation of a variety of important elements including C, N, O and transition metals is possible. Specific atomic sites and electronic states can be selectively characterized by the Resonant momentum-resolved photoelectron spectroscopy [10,11]. Furthermore, a branch was added to BL7U, an undulator-based vacuum ultraviolet (VUV 6-40 eV) beamline (Fig.1). In addition to grazing-incidence soft X-ray excitation, normal-incidence VUV with variable polarization (horizontal/vertical/circular) excitation is also available at the same focal position of the PMM.
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