-------------------------------------------------------------------------- ### Surface-symmetry-driven-Dzyaloshinskii-Moriya interaction and canted ferrimagnetism in collinear magnetoelectric antiferromagnet Cr_2O_3 -------------------------------------------------------------------------- Oleksandr V. Pylypovskyi, Sophie F. Weber, Pavlo Makushko, Igor Veremchuk, Nicola A. Spalin, Denys Makarov -------------------------------------------------------------------------- ### Abstract: Antiferromagnets are normally thought of as materials with compensated magnetic sublattices. This adds to their technological advantages but complicates readout of the antiferromagnetic state. We demonstrate theoretically the existence of a Dzyaloshinskii-Moriya interaction (DMI) which is determined by the magnetic symmetry classes of Cr2O3 surfaces with an in-plane magnetic easy axis. The DMI explains a previously predicted out-of-plane magnetization at the nominally compensated surfaces of chromia, leading to a surface-localized canted ferrimagnetism. This is in agreement with magnetotransport measurements and with density functional theory predictions which further allow us to quantify the strength of DMI. The temperature dependence of the transversal resistance for these planes shows distinct behavior in comparison with that of the Cr2O3 plane, which we attribute to the influence of DMI. Our work provides a framework to analyze surface-driven phenomena in antiferromagnets, and motivates the use of nominally compensated chromia surfaces for antiferomagnetic spintronics and magnonics. -------------------------------------------------------------------------- This record includes input files and relevant output files for the DFT and Monte Carlo calculations used for figures in the main text and supplement of the submitted manuscript (experimental data is archived separately). The naming of the tar files refers to the type of calculation performed, e.g. aplane_2ndlayercant.tar contains DFT files for calculations involving canting the second layer of Cr moments in an a-plane-oriented Cr2O3 slab while keeping the canting angle of the top surface layer fixed. Note that some of the tar files contain VASP input files that are outside the subdirectories; these are just input files which remain constant and are copied to each subdirectory. The mplane_LzMx and aplane_LzMx tar files each contain two sets identical calculations performed with opposite antiferromagnetic domains (i.e. switching the sign of the Neel vector), which are just called "domain1 and "other domain". The subdirectories with numbers at titles refer to the angle in degrees at which the surface Cr moments are canted with respect to the Neel vector direction. The "mvec_100surf_CrN" text files in the Monte Carlo tar file are the processed output files with columns referring to x, y and z components of magnetization for the Nth chromium sublattice in the m-plane slab used in the simulation. The rows are for the different temperature values, specified in the runme.sh file, at which the simulations are performed. DFT calculations were performed with VASP version 5.4.4. Monte Carlo calculations with performed with the UppASD code v5.1.1.