<p>INTRODUCTION</p><p>Physical property exploration using light has revealed many previously unknown physical properties. Electronic and nuclear spin states of surface-adsorbed molecules [1,2], characterization of electronic states using X-ray absorption spectroscopy (XAS) has been proposed [3,4]. Wavenumber-resolved photoemission spectroscopy is a powerful method for studying the electronic structure of crystals [5]. Advances in detectors have made it possible to obtain highly accurate 3D maps compared to conventional 2D maps obtained by Angle-resolved photoemission spectroscopy (ARPES). Since it can quickly measure from metals to organic thin films, all kinds of measurements are possible. A material design for spin orbitronics devices with a dramatic energy-saving function is desired. Atomic-layer crystals stacked via van der Waals forces are candidates for this. Bi2Se3 is a strong topological insulator, possessing a Dirac-conical surface dispersion connecting the conducting and valence states. It has been thought that the spin direction is determined by the electron momentum. However, recently, it was found that this spin state is maintained only under a specific optical geometry, and it was reported that the spin state in solids is an entanglement state [6].</p><p></p><p>RESULTS AND DISCUSSION</p><p>In this presentation, we calculated wavenumber-resolved photoemission spectra of layered materials such as Bi2Se2 and TiSe2. The initial and final states were calculated based on density functional theory (DFT), and the photoelectron intensity was calculated. At this time, boundary conditions on the surface were considered. Compared to the methods we have reported so far [7-10], it has the advantage that the surface electronic state can be considered in detail, and the scattering term in the final state can also be included.</p><p></p><p>REFERENCES</p><p>[1] K. Niki et al., Phys. Rev. B 77, 201404 (R) (2008).</p><p></p><p>[2] K. Niki et al., Phys. Rev. B 79, 085408 (2009).</p><p></p><p>[3] J. Kogo et al., J. Phys. Soc. Jpn. 91, 034702 (2022).</p><p></p><p>[4] T. Fujikawa et al., J. Electron Spectros. Relat. Phenom. 233, 57 (2019).</p><p></p><p>[5] S. Suga and A. Sekiyama, Springer Series in Optical sciences 176, (2013).</p><p></p><p>[6] K. Kuroda a et al., Phys. Rev. B 94, 165162 (2016).</p><p></p><p>[7] M. Kazama et al., Phys. Rev. B (R), 89, 045110, (2014).</p><p></p><p>[8] T. Fujikawa and K. Niki, J. Electron Spectros. Relat. Phenom. 206, 74 (2016).</p><p></p><p>[9] K. Niki et al., Vacuum and Surf. Sci. 63, 336 (2020).</p><p></p><p>[10] K. Baumgärtner et al., arXiv:2305.07773.</p>