Thickness and surface-termination effects on magnetocrystalline anisotropy of FeM (M$=$Rh, Cr, and Pt) (001) thin films

FeM (M$=$Rh, Cr, and Pt) alloys show diverse interesting physical properties,\footnote{X. Mart et al., Nature Mater. \textbf{13}, 367 (2014)}$^,$\footnote{S. L. Qiu, P. M. Marcus, and V. L. Moruzzi, J. Appl. Phys. \textbf{85}, 4839 (1999).}$^,$\footnote{G. Brown, B. Kraczek, A. Janotti, T. C. Schulthess, G. M. Stocks, and D. D Johnson, Phys. Rev. B \textbf{68}, 052405 (2003).} which attracted these alloys as a promising candidate for spintronics application.\footnote{X. Mart, et al.} In this study, we investigate effects of thickness and surface-termination on magnetism and magnetocrystalline anisotropies (MCAs) on the CsCl-structured FeM(001) thin films, using Vienna Ab initio Simulation Package. Two surface terminations (Fe-terminated and M-terminated) and thicknesses from 3 to 15 monolayers are taken into account. We find that magnetism and MCAs are sensitive to the surface termination and the thickness, whose relevance to electronic structures will be discussed.