Hi, Did you use mBJ to calculate the band gap in both procedures?
FT On Thursday 2018-02-08 09:35, Dr. K. C. Bhamu wrote:
Date: Thu, 8 Feb 2018 09:35:08 From: Dr. K. C. Bhamu <kcbham...@gmail.com> Reply-To: A Mailing list for WIEN2k users <email@example.com> To: A Mailing list for WIEN2k users <Wien@zeus.theochem.tuwien.ac.at> Subject: [Wien] a note on lattice parameter optimization Hello, Using experimental lattice parameters(a Ang), I optimized the structure with two options. 1. Directly optimized the structure without min_lapw ... and the optimized lattice parameters are in the vicinity of Exp a (~0.01 Ang accuracy) and the calculated band gap (from mBJ2) is in agreement with reported value ~0.3 eV less. 2. First relaxed the structure and then optimized this relaxed structure (without min_lapw ....). In this case the optimized lattice parameters are reduced by ~0.05 Ang and the band gap vanished or largely reduced. Why is the second way of doing band structure not working? I tested it on many systems. In some case system became metal and in some cases band gap largely reduced when I used the fully relaxed structure for optimization. Thanks, Bhamu
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