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arXiv · 2601.19652

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
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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.

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N. Yu. Solovova, V. A. Golyashov, S. V. Eremeev, S. Yu. Priobrazhenskii, S. P. Lebedev, A. A. Lebedev, V. S. Rusetsky, O. E. Tereshchenko. 2026-01-27. Revealing the (111) surface electronic structure of epitaxially grown Na$_2$KSb photocathode. https://doi.org/10.1016/j.apsusc.2026.167213

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