Coupled structural distortions, domains, and control of phase competition in polar SmBaMn${}_2$O${}_6$

Abstract

Materials with coupled or competing order parameters display highly tunable ground states, where subtle perturbations reveal distinct electronic and magnetic phases. These phases generally are underpinned by complex crystal structures, but the role of structural complexity in these phases often is unclear. We use group theoretic methods and first-principles calculations to analyze a set of coupled structural distortions that underlie the polar charge- and orbitally- ordered antiferromagnetic ground state of $A$-site ordered SmBaMn${}_2$O${}_6$. We show that these distortions play a key role in establishing the ground state and stabilizing a network of domain wall vortices. Furthermore, we show that the crystal structure provides a knob to control competing electronic and magnetic phases at structural domain walls and in epitaxially strained thin films. These results provide new understanding of the complex physics realized across multiple length scales in SmBaMn${}_2$O${}_6$ and demonstrate a framework for systematic exploration of correlated and structurally complex materials.

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• Restoring the density-gradient expansion for exchange in solids and surfaces
• Generalized gradient approximation for solids and their surfaces
• Experimental demonstration of hybrid improper ferroelectricity and presence of abundant charged walls in (Ca,Sr)${}_3$Ti${}_2$O${}_7$ crystals
• Aperiodic topological order in the domain configurations of functional materials

Cited by in corpus (1)

• Ground-state structure, orbital ordering and metal-insulator transition in double-perovskite PrBaMn2O6