Xiangyang Huang

First-principles study of symmetry lowering and polarization in BaTiO3/SrTiO3 superlattices with in-plane expansion

The crystal structure and local spontaneous polarization of (BaTiO3)m/(SrTiO3)n superlattices is calculated using a first-principles density functional theory method. The in-plane lattice constant is 1% larger than the SrTiO3 substrate to imitate the relaxed superlattice structure and the symmetry is lowered to monoclinic space group Cm which allows polarization to develop along the [110] and [001] directions. The polarization component in the [110] direction is found to develop only in the SrTiO3 layers and falls to zero in the BaTiO3 layers, whereas the polarization in the [001] direction is approximately uniform throughout the superlattice. These findings are consistent with recent experimental data and first-principles results for epitaxially strained BT and ST.

Structural, electronic, and magnetic properties of Sr Ru O 3 under epitaxial strain

Using density functional theory within the local spin density approximation, the structural, electronic, and magnetic properties of

First-principles thermodynamics of transition metals: W, NiAl, and PdTi

\mathrm{Sr}\mathrm{Ru}{\mathrm{O}}_{3}

Structural, electronic, and magnetic properties ofSrRuO3under epitaxial strain

are investigated. We examine the magnitude of the orthorhombic distortion in the ground state and also the effects of applying epitaxial constraints, whereby the influence of large (in the range of

Structural, electronic and magnetic properties of SrRuO

\ifmmode\pm\else\textpm\fi{}4%

_3

) in-plane strain resulting from coherent epitaxy, for both [001] and [110] oriented films, has been isolated and investigated. The overall pattern of the structural relaxations reveals coherent distortions of the oxygen octahedron network, which determine the stability of the magnetic moment on the Ru ion. The structural and magnetic parameters exhibit substantial changes, allowing us to discuss the role of symmetry and possibilities of magnetostructural tuning of

under epitaxial strain

\mathrm{Sr}\mathrm{Ru}{\mathrm{O}}_{3}

Crystal structures and shape-memory behaviour of NiTi

-based thin-film structures.

Manipulating magnetic properties ofSrRuO3andCaRuO3with epitaxial and uniaxial strains

We apply the pseudopotential density-functional-perturbation theory approach along with the quasiharmonic approximation to calculate the thermal expansion of tungsten and two important metallic alloys NiAl and PdTi. We derive the theory for anisotropic crystal structures and test the approximation that the anisotropic effects of thermal expansion are equivalent to negative pressure-this simplifies the calculation enormously for complex structures. Throughout, we find excellent agreement with experimental results.

Lattice instabilities of cubic NiTi from first principles

Using density functional theory within the local spin density approximation, the structural, electronic, and magnetic properties of