SciPost Submission Page
Assessing the role of interatomic position matrix elements in tight-binding calculations of optical properties
by Julen Ibañez-Azpiroz, Fernando de Juan, Ivo Souza
This Submission thread is now published as
Submission summary
| Authors (as registered SciPost users): | Julen Ibanez · Ivo Souza · Fernando de Juan |
| Submission information | |
|---|---|
| Preprint Link: | scipost_202112_00037v1 (pdf) |
| Date accepted: | 2022-01-13 |
| Date submitted: | 2021-12-16 17:01 |
| Submitted by: | Ibanez, Julen |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
|
| Approaches: | Theoretical, Computational |
Abstract
We study the role of hopping matrix elements of the position operator $\mathbf{\hat{r}}$ in tight-binding calculations of linear and nonlinear optical properties of solids. Our analysis relies on a Wannier-interpolation scheme based on \textit{ab initio} calculations, which automatically includes matrix elements of $\mathbf{\hat{r}}$ between different Wannier orbitals. A common approximation, both in empirical tight-binding and in Wannier-interpolation calculations, is to discard those matrix elements, in which case the optical response only depends on the on-site energies, Hamiltonian hoppings, and orbital centers. We find that interatomic $\mathbf{\hat{r}}$-hopping terms make a sizeable contribution to the shift photocurrent in monolayer BC$_2$N, a covalent acentric crystal. If a minimal basis of $p_z$ orbitals on the carbon atoms is used to model the band-edge response, even the dielectric function becomes strongly dependent on those terms.
Author comments upon resubmission
List of changes
- We switched the n,m indexes in the definition of $\omega_{nm}$
- We moved the expression of the 2x2 k.p Hamiltonian from Appendix A into the main text
- We fixed the typo mentioned by the referee
Published as SciPost Phys. 12, 070 (2022)