Anisotropic soft X-ray emission spectroscopy study of the valence electron state of Lu(Al,T)B₄ (T= Cr, Mn, Fe, Mo) exhibiting two-dimensional B-layers

¹ IMRAM, Tohoku University, Sendai 980-8577, Japan
² AMA Co-Creation Research Center, Tohoku University, Sendai 980-8577, Japan
³ Departmen of Science and Engineering, Kokushikan University, Tokyo 154-8515, Japan
⁴ Research Institute for Engineering, Kanagawa University, Yokohama 221-8686, Japan

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Published online: 29 January 2026

Abstract

Lu(Al,T)B₄ (T= Cr, Mn, Fe, Mo) have the alternate stacking structure of B-layer and Lu(Al,T)-layer along the c-axis. B-K emission spectra of these materials are measured at two take-off angles of 20° and 70° from the c-plane. The energy region corresponding to the top of valence band (VB) shows a larger spectrum intensity at the smaller take-off angle, responsible for p_z character. The bottom region shows the opposite angle dependence, responsible for p_x and p_y character. The middle of the VB of a large peak intensity shows almost no angle dependence, suggesting an isotropic distribution of bonding charge. As a whole, the angle-dependence of the B-K emission intensity is smaller than that of graphite. This rather isotropic bonding-charge distribution of the boron-layer can make the inter-layer bonding between B-layer and adjacent Lu(Al,T) layer and is presumably related to the hardness of those bulk materials.