Motion (physics)

Gene

Quantum mechanics

Diagonal

Photocurrent

Perturbation theory (quantum mechanics)

Materials science

Wannier function

Eigenvalues and eigenvectors

Electronic structure

Biochemistry

Ab initio

Mathematical optimization

Hamiltonian (control theory)

Interpolation (computer graphics)

Classical mechanics

Diagonalizable matrix

Physics

Tight binding

Mathematics

Molecular physics

Symmetric matrix

Condensed matter physics

Transcription factor

Mathematical analysis

Computational chemistry

Geometry

Repressor

Hamiltonian matrix

Chemistry

Subspace topology

Operator (biology)

Physical review. B./Physical review. B

We describe and implement a first-principles algorithm based on maximally-localized Wannier functions for calculating the shift-current response of piezoelectric crystals in the independent-particle approximation. The proposed algorithm presents several advantages over existing ones, including full gauge invariance, low computational cost, and a correct treatment of the optical matrix elements with nonlocal pseudopotentials. Band-truncation errors are avoided by a careful formulation of $k\cdot p$ perturbation theory within the subspace of wannierized bands. The needed ingredients are the matrix elements of the Hamiltonian and of the position operator in the Wannier basis, which are readily available at the end of the wannierization step. If the off-diagonal matrix elements of the position operator are discarded, our expressions reduce to the ones that have been used in recent tight-binding calculations of the shift current. We find that this `diagonal' approximation can introduce sizeable errors, highlighting the importance of carefully embedding the tight-binding model in real space for an accurate description of the charge transfer that gives rise to the shift current.

<i>Ab initio</i> calculation of the shift photocurrent by Wannier interpolation

Ab initio calculation of the shift photocurrent by Wannier interpolation