arXiv subjects

Alison J. Hatt

Publications and source records attributed to Alison J. Hatt.

2 recordsLinked to original sources

arXiv2010

Structural phases of strained LaAlO3 driven by octahedral tilt instabilities

We investigate the effect of epitaxial strain on [001]-oriented LaAlO3 using first-principles density functional calculations. We find a series of structural phase transitions between states characterized by distinct patterns of tilting of the AlO6 octahedra. By tuning the biaxial strain from compressive to tensile, we induce an evolution in the crystal structure in which the tilt axis changes from out-of-plane to in-plane, corresponding to space groups I4/mcm and Imma. We also study the effect of uniaxial relaxation of the usual biaxial epitaxial constraint and explore this as a mechanism for selectively stabilizing different patterns of octahedral tilts.

cond-mat.mtrl-sci↗

arXiv2007

Tri-layer superlattices: A route to magnetoelectric multiferroics?

We explore computationally the formation of tri-layer superlattices as an alternative approach for combining ferroelectricity with magnetism to form magnetoelectric multiferroics. We find that the contribution to the superlattice polarization from tri-layering is small compared to typical polarizations in conventionalferroelectrics, and the switchable ferroelectric component is negligible. In contrast, we show that epitaxial strain and ``negative pressure'' can yield large, switchable polarizations that are compatible with the coexistence of magnetism, even in materials with no active ferroelectric ions.

cond-mat.mtrl-sci↗