Thermodynamic stability of twisted domains in AgCrSe$_{2}$ thin films grown on lattice-matched YSZ(111) substrate

Abstract

Control of structural domains in epitaxial thin films of functional materials is a fundamental technique to utilize their intrinsic physical and chemical properties in solid-state devices. In this study, we report on suppression of twisted-domain formation in thin-film growth of polar magnetic semiconductor AgCrSe$_{2}$ using pulsed-laser deposition. In exploring concomitant optimized growth temperature and Ag/Cr composition ratio of supply, we find the critical growth temperature ($T\mathrm{_{sub}}$) for obtaining single 60$^{\circ}$ domain in c-axis oriented AgCrSe$_{2}$ thin film on a lattice-matched (111) plane of the yttria-stabilized zirconia substrate. At temperatures below and above the critical $T\mathrm{_{sub}}$, metastable 0$^{\circ}$ domain in addition to the 60$^{\circ}$ domain emerges, indicating delicate energy balance of thermodynamic stability for obtaining the single-domain structure. Surface structural analysis using time-of-flight low-energy atom scattering spectroscopy reveals the presence of two polar orientations along $+Z$ and $-Z$ directions. These findings provide valuable insights into the thin-film growth mechanisms for a family of two-dimensional compounds with rhombohedral lattices.