Revealing the (111) surface electronic structure of epitaxially grown Na$_2$KSb photocathode

N. Yu. Solovova; V. A. Golyashov; S. V. Eremeev; S. Yu. Priobrazhenskii; S. P. Lebedev; A. A. Lebedev; V. S. Rusetsky; O. E. Tereshchenko

doi:10.1016/j.apsusc.2026.167213

paper

Revealing the (111) surface electronic structure of epitaxially grown Na $_{2}$ KSb photocathode

arXiv:2601.19652 · doi:10.1016/j.apsusc.2026.167213

Abstract

A recent study has established the Na $_{2}$ KSb(Cs) photocathode as a highly efficient emitter of spin-polarized electrons. However, the electronic structure of alkali antimonides remains poorly understood. In this work, we report the first crystalline epitaxial growth of Na $_{2}$ KSb films, achieved via chemical vapor deposition (CVD) on a graphene-coated SiC(0001) substrate. The high crystalline quality of these films enabled a direct investigation of the material's electronic structure using angle-resolved photoemission spectroscopy (ARPES). By comparing the experimental results with density functional theory (DFT) calculations, we have identified dispersive surface states originating from different terminations of the Na $_{2}$ KSb(111) surface. Furthermore, we demonstrate that the crystalline order of the film is preserved following its activation via the deposition of Cs and Sb. This finding opens a pathway for investigating the electronic structure of multialkali Na $_{2}$ KSb(Cs) photocathodes and for rationally improving their properties.

12 pages, 3 figures

Revealing the (111) surface electronic structure of epitaxially grown Na2​KSb photocathode

Abstract

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Revealing the (111) surface electronic structure of epitaxially grown Na $_{2}$ KSb photocathode