The importance of solid-state surfaces for many applications, from electronics to heterogenous catalysis, has been known for decades. Less established is the fact that surfaces are also a platform for emergent phenomena, such as a net surface magnetization, or a net surface polarization, that are forbidden by symmetry constraints from existing deep inside the material bulk. These emergent surface phenomena have the potential to transform current device architectures, in particular for spintronics applications where the electron spin degree of freedom, in addition to its charge, is used to store and transport information. Although the theoretical concept of low-symmetry surface properties has been been known (but under-recognized) for some time, first-principles calculations that quantitatively predict and characterize these emergent surface properties in realistic materials are still in their infancy. In the ongoing and upcoming projects which will be enabled by this medium compute project, we will use first-principles density functional theory (DFT) supplemented with Wannier-based tight binding models and Monte Carlo simulations to achieve two broad goals related to advancing the qualitative and quantitative understanding of surface phenomena. First we will continue to leverage symmetry analysis combined with the above computational methods to predict and characterize new emergent magnetic, electronic and structural properties at solid-state surfaces, interfaces and in low-dimensional materials. A second, closely related theme is to combine ab-initio calculations with model Hamiltonians to understand how surface effects can manifest in realistic materials subjected to experimental conditions, such as at finite temperatures and under applied electromagnetic fields. Ongoing and planned projects for which we will use this medium compute allocation are the following: 1. Symmetry and DFT-based investigation of interfacial properties in antiferromagnetic-heavy metal heterostructures (ongoing, months 1-12). 2. High-throughput discovery and DFT-based characterization of new magnetoelectric materials (ongoing, months 1-6). 3. DFT-based understanding of experimentally observed surface magnetic reconstructions in FeTe (ongoing, months 1-6)) 4. Symmetry-guided DFT- and Wannier-based prediction and characterization of surface-localized anomalous transport responses and surface magnetization for antiferromagnetic readout (Planned, months 7-12) 5. Combined symmetry, DFT, and Monte Carlo study of exchange bias for nominally compensated antiferromagnetic-ferromagnetic interfaces. (Planned, months 7-12) 6. DFT-based study on the quantitative link between bulk magnetic multipoles and surface magnetization and magnetoelectricity (ongoing, months 1-6). The broad range of properties to be investigated in this proposal necessitates a variety of methods with differing levels of computational overhead. To account for localized unpaired electrons DFT+U will be used. Constrained, noncollinear DFT will also be leveraged to explore energy landscapes as a function of magnetic order. For magnetoelectric properties, we will simulate applied electric fields within DFT at various levels of theory. Wannierization of DFT Kohn-Sham eigenfunctions using Wannier90 will enable efficient evaluation of transport tensors. Finally, we will evaluate temperature and field-dependent magnetic properties (in particular hysteresis loops for project 5) using Monte Carlo simulations with DFT-derived magnetic parameters as input.