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General Questions and Answers / Issue with relaxation convergence in Charged Point Defect calculation
« on: January 19, 2026, 08:06 »
I am currently performing Charged Point Defect (CPD) calculations on Al-doped HfO2 supercells.
I have prepared optimized pristine cells for two compositions: Hf54Al10O123 (Hf-rich) and Hf32Al32O112 (Al-rich). While the calculation works fine for the Hf-rich composition, the relaxation for the Al-rich composition (Hf32Al32O112) fails to converge even after reaching 300 steps.
Here are the calculation details:
Calculator: GGA-PBESol
System Size: 176 atoms
K-point Sampling: 1x1x1
Electron Temperature (Broadening): 300 K
Optimization Settings: Max step length = 0.07 Å
Iteration Control Parameters:
Damping factor = 0.05
Number of history steps = 6
Effective rank fraction = 0.06
I have also verified that the forces are stable and do not fluctuate significantly when tested with 1x1x2 and 2x2x1 k-point grids.
Could you please provide any suggestions on how to resolve this convergence issue? Any help would be greatly appreciated.
I have prepared optimized pristine cells for two compositions: Hf54Al10O123 (Hf-rich) and Hf32Al32O112 (Al-rich). While the calculation works fine for the Hf-rich composition, the relaxation for the Al-rich composition (Hf32Al32O112) fails to converge even after reaching 300 steps.
Here are the calculation details:
Calculator: GGA-PBESol
System Size: 176 atoms
K-point Sampling: 1x1x1
Electron Temperature (Broadening): 300 K
Optimization Settings: Max step length = 0.07 Å
Iteration Control Parameters:
Damping factor = 0.05
Number of history steps = 6
Effective rank fraction = 0.06
I have also verified that the forces are stable and do not fluctuate significantly when tested with 1x1x2 and 2x2x1 k-point grids.
Could you please provide any suggestions on how to resolve this convergence issue? Any help would be greatly appreciated.