RELIABLE PREDICTION OF ELECTRONIC AND OPTICAL PROPERTIES OF LAYERED AND 2D MATERIALS FROM TRANSFERABLE SCREENED RANGE-SEPARATED HYBRID FUNCTIONALS
Abstract
The electronic band structure is a fundamental property of crystalline matter. It serves as the basis for understanding charge transport properties of bulk materials. Moreover, it is a prerequisite for understanding optical properties of materials and for rationalizing the results of spectroscopic measurements. Electronic and optical excitations are often calculated from first principles using many-body perturbation theory (MBPT), where single- and two-particle excitation energies are computed from suitable approximations of the one- and two-particle Green function, respectively. But GW-BSE is often too expensive to use regularly and for unexplored materials there can be significant debate on best practices for such calculations. Obtaining accurate solid-state band structures from density functional theory (DFT), based on the single-electron energies and orbitals obtained from the solution of the Kohn-Sham equation, could reduce the computational burden of MBPT. However, DFT has traditionally struggled to predict electronic structure with spectroscopic accuracy. In particular, band gap prediction from DFT is notoriously problematic. However, we have introduced optimally tuned range-separated hybrid (OTRSH) functionals as a systematic route for the prediction of ionization potentials and fundamental gaps in molecular systems. In the RSH approach, the repulsive inter-electron Coulomb potential is range-split, allowing the separate treatment of each interaction range. We choose it such that it reduces in the long-range to the Hartree–Fock approximation (allowing for an asymptotically correct potential) but reduces to a semi-local or a conventional hybrid functional in the short-range (thereby retaining the careful balance between exchange and correlation that these functionals offer). In the optimal tuning approach, one chooses the range-separation parameter (whose value controls the transition between short- and long-range interactions) non-empirically.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 11, 2021
- Source ID
- FA86552017041
Entities
People
- Leeor Kronik
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- Weizmann Institute of Science