Hse06 Vasp — !exclusive!

SYSTEM = ZnO HSE06 ENCUT = 520 ISMEAR = -5 # Tetrahedron method for DOS SIGMA = 0.05 PREC = Accurate LHFCALC = .TRUE. HFSCREEN = 0.2 AEXX = 0.25 GGA = PE ALGO = Damped TIME = 0.4

If your system has less than 50 atoms and you care about the band gap to 0.1 eV accuracy, pay the cost. If you're studying a metal or a giant interface, stick with PBE+U. Have you had success (or nightmares) running HSE06? Let me know in the comments below. And yes, your SCF will oscillate on the first try—check your mixing parameters. hse06 vasp

ALGO = Damped # Damped algorithm (often more stable than Normal) TIME = 0.4 # Mixing time (increase from default 0.1) BMIX = 0.0001 # Small mixing parameter AMIN = 0.01 # Avoid Pulay collapse If still failing, try ALGO = All (fast but memory hungry) or IALGO = 53 (very stable but slow). | System | PBE wall time | HSE06 wall time | Memory | | :--- | :--- | :--- | :--- | | Si (8 atoms, 6x6x6 kpoints) | 2 min | 20 min | 2x | | TiO₂ (12 atoms, 4x4x4) | 5 min | 1.5 hours | 3x | | NiO (8 atoms, 8x8x8) | 3 min | Fails / 4 hours | 5x | SYSTEM = ZnO HSE06 ENCUT = 520 ISMEAR

Why "screened"? Because in a metal, the Coulomb interaction dies off quickly. HSE06 introduces a screening parameter ($\omega$) to cut off the long-range HF exchange, making it computationally feasible for periodic systems. Have you had success (or nightmares) running HSE06

Enter (Heyd-Scuseria-Ernzerhof). This hybrid functional has become the gold standard for "affordable accuracy" in solid-state physics. But let’s be real—it comes at a computational cost.

If you have spent any time running density functional theory (DFT) calculations, you know the drill: PBE (Perdew-Burke-Ernzerhof) is fast, reliable, and often... wrong. It systematically underestimates band gaps, over-delocalizes electrons, and struggles with strongly correlated materials.