Engineered substrates for domain control in CrSe thin-film growth: single-domain formation on a lattice-matched YSZ(111) substrate

Abstract Epitaxial thin-film growth is a versatile and powerful technique for achieving precise control of composition, stabilizing non-equilibrium phases, tailoring growth orientation, as well as forming heterointerfaces of various quantum materials. For the synthesis of highly crystalline thin films, an in-depth understanding of the epitaxial relationship between the desired thin film and the single-crystalline substrates is necessary. In this study, we investigate the epitaxial relationship in thin-film growth of triangular-lattice antiferromagnet CrSe on the (001) plane of Al 2 O 3 and the lattice-matched (111) plane of yttria-stabilized zirconia (YSZ) substrates. Structural characterization using out-of-plane and in-plane X-ray diffraction shows that the 19.1°-twisted domains of CrSe significantly dominate the aligned domain on the Al 2 O 3 substrate while it reveals a single-domain formation on the YSZ substrate. The stability of the 19.1°-twisted domain rather than the aligned domain can be explained by rotational commensurate epitaxy, which is well reproduced by density functional theory calculations. The single-domain CrSe thin film on the YSZ substrate exhibits a superior metallic conductivity compared to the twisted-domain thin film on the Al 2 O 3 substrate, implying the contribution of the grain boundary scattering mechanism to electrical transport.