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 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 | Enter (Heyd-Scuseria-Ernzerhof)
In older VASP versions (pre-6), you needed LHFCALC = .TRUE. and HFSCREEN = 0.2 . In VASP 6+, you can also use HSE06 as a pseudopotential flag, but the manual INCAR approach is safer. Step 2: FFT grids and precision Hybrid functionals are sensitive to the real-space grid. Use high precision: If your system has less than 50 atoms
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