Forces and atomic relaxations in the pSIC approach with ultrasoft pseudopotentials

Abstract

We present the scheme that allows for efficient calculations of forces in the framework of pseudopotential self-interaction corrected (pSIC) formulation of the density functional theory. The scheme works with norm conserving and also with ultrasoft pseudopotentials and has been implemented in the plane-wave basis code {\sc quantum espresso}. We have performed tests of the internal consistency of the derived expressions for forces considering ZnO and CeO${}_2$ crystals. Further, we have performed calculations of equilibrium geometry for LaTiO${}_3$, YTiO${}_3$, and LaMnO${}_3$ perovskites and also for Re and Mn pairs in silicon. Comparison with standard DFT and DFT+U approaches shows that in the cases where spurious self-interaction matters, the pSIC approach predicts different geometry, very often closer to the experimental data.

11 pages, 2 figures

References in corpus (2)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Fermi-surface pockets in $YB{a}_{2}C{u}_3{O}_{6.5}$ : A comparison of ab initio techniques

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