Origin of two-dimensional electronic states at Si- and Gd-terminated surfaces of GdRh2Si2(001)

We acknowledge support by the Academic D. I. Mendeleev Fund Program of Tomsk State University (Project No. 8.1.01.2018), a Saint Petersburg State University grant for scientific investigations (Grant No. 15.61.202.2015), and the Fundamental Research Program of the State Academies of Sciences for 2019–2021 (line of research III.23.2.9). Support by the Basque Departamento de Educacion, UPV/EHU (Grant No. IT-756-13), and Spanish Ministerio de Economia y Competitividad (MINECO Grant No. FIS2016-75862-P) is also acknowledged. We acknowledge financial support from the Spanish Ministry of Economy (MAT-2017-88374-P). The calculations were performed at the Research park of St. Petersburg State University «Computing Center», at the SKIF Cyberia cluster of Tomsk State University, and at Donostia International Physics Center.