Topological Properties of SnSe/EuS and SnTe/CaTe Heterostructures

We use density functional theory (DFT) to study epitaxial interfaces of the topological crystalline insulators SnSe and SnTe with the ferromagnetic semiconductor EuS and the nonmagnetic semiconductor CaTe, respectively. We consider both surface slab models and periodic "sandwich" heterostructures. We find that a gapped surface state arises in the SnSe/EuS interface due to the magnetic proximity effect. By comparison, the gapless topological surface state at the interface of SnTe/CaTe is unperturbed.