We derive the stress-tensor formula within the LSDA+U scheme by differentiating analytically the LSDA+U total-energy function with respect to the strain tensor. The rotationally invariant form of the LSDA+U functional is employed and the double-counting correction is considered in the fully localized limit and around mean field. The electronic wave functions are expanded with either pseudoatomic orbitals (PAOs) or plane waves. In the PAO-basis case, the orthogonality stress term is included. Our LSDA+U stress-tensor formula is numerically tested with antiferromagnetic NiO and reproduces successfully the stress values obtained from numerical derivatives of the total-energy values. As an application, we study elastic constants, bulk moduli, and sound velocities of NiO and MnO, obtaining results in good agreement with experimental data.
Bibliographical noteFunding Information:
This work was supported by National Research Foundation of Korea (Grant No.2011-0018306). Computational resources were provided by the KISTI Supercomputing Center (Project No. KSC-2015-C3-039)
© 2016 American Physical Society.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics