Challenges with relativistic GW calculations in solids and molecules

Area of Science:

• Computational Chemistry
• Quantum Mechanics
• Materials Science

Background:

• Accurate electronic-structure calculations for heavy elements necessitate considering both electron correlation and relativistic effects.
• Relativistic effects significantly alter molecular ground states and can induce phase changes in solids.
• Traditional methods involve pseudopotentials or large all-electron basis sets.

Purpose of the Study:

• To investigate the challenges in capturing the interplay of relativity and electron correlation in Green's function methods.
• To analyze electronic properties in semiconductors and insulators with heavy elements.
• To identify persistent problems in molecular calculations involving heavy elements.

Main Methods:

• Analysis of electronic properties: band structure, equilibrium lattice constant, and bulk modulus.
• Application of Green's function methods to molecules and solids with heavy elements.
• Investigation of pseudopotential treatments and all-electron basis sets.

Main Results:

• Capturing the interplay of relativity and electron correlation is challenging in Green's function methods.
• Deficiencies were observed in pseudopotential treatments and all-electron basis sets.
• Linear dependencies in all-electron basis sets, especially with Gaussian orbitals, were identified.

Conclusions:

• The study highlights critical issues in computational methods for heavy elements.
• Problems stem from pseudopotential deficiencies, basis set limitations, and linear dependencies.
• Opens discussion for potential solutions to improve accuracy in relativistic electronic-structure calculations.