On the calculation of the bandgap of periodic solids with MGGA functionals using the total energy

TL;DR

This paper presents a non-self-consistent method to accurately calculate the bandgap of periodic solids using MGGA functionals based solely on total energy, simplifying implementation and potentially speeding up computations.

Contribution

It introduces a novel non-self-consistent approach for bandgap calculation with MGGA functionals that does not require potential implementation.

Findings

Accurate bandgap calculations using total energy only.

Applicable to functionals with complex potentials.

Simplifies and accelerates electronic structure computations.

Abstract

During the last few years, it has become more and more clear that functionals of the meta generalized gradient approximation (MGGA) are more accurate than GGA functionals for the geometry and energetics of electronic systems. However, MGGA functionals are also potentially more interesting for the electronic structure, in particular when the potential is non-multiplicative (i.e., when MGGAs are implemented in the generalized Kohn-Sham framework), which may help to get more accurate bandgaps. Here, we show that the calculation of bandgap of solids with MGGA functionals can be done very accurately also in a non-self-consistent manner. This scheme uses only the total energy and can, therefore, be very useful when the self-consistent implementation of a particular MGGA functional is not available. Since self-consistent MGGA calculations may be difficult to converge, the non-self-consistent scheme may also help to speed-up the calculations. Furthermore, it can be applied to any other types of functionals, for which the implementation of the corresponding potential is not trivial.