I find a band reversal in the GW results compared with the PBE ones. My system is 2D with a direct PBE gap of 0.008303 eV(at the k point of 49). And the GW results are as follows:
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QP [eV] @ K [49] (iku): -0.500000 -0.500000 0.000000
B=60 Eo= -2.36 E= -2.53 E-Eo= -0.17 Re(Z)=0.75 Im(Z)=-0.214399E-2 nlXC= -22.5032 lXC= -18.0008 So= 4.27851
B=61 Eo= -2.34 E= -2.27 E-Eo= 0.07 Re(Z)=0.75 Im(Z)=-0.117164E-2 nlXC= -16.8008 lXC= -15.0595 So= 1.83684
B=62 Eo= -1.93 E= -1.90 E-Eo= 0.03 Re(Z)=0.75 Im(Z)=-0.205785E-2 nlXC= -17.4891 lXC= -15.2494 So= 2.27820
B=63 Eo= 0.00 E= 0.66 E-Eo= 0.66 Re(Z)=0.76 Im(Z)=-0.213259E-2 nlXC= -12.8546 lXC= -15.1054 So= -1.38438
B=64 Eo= 0.01 E= 0.46 E-Eo= 0.45 Re(Z)=0.76 Im(Z)=-0.204936E-2 nlXC= -12.0753 lXC= -14.2854 So= -1.62188
B=65 Eo= 0.05 E= 0.76 E-Eo= 0.71 Re(Z)=0.76 Im(Z)=-0.207785E-2 nlXC= -12.6966 lXC= -15.3515 So= -1.72120
B=66 Eo= 1.79 E= 2.72 E-Eo= 0.93 Re(Z)=0.76 Im(Z)=-0.147795E-2 nlXC= -8.64970 lXC= -13.6453 So= -3.77699
B=67 Eo= 2.03 E= 2.96 E-Eo= 0.93 Re(Z)=0.76 Im(Z)=-0.162771E-2 nlXC= -8.69498 lXC= -13.6545 So= -3.73556
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I think the gap should be (0.66-0.46) but here the VBM is larger than the CBM. And consequently, the following BSE process reads the gap from ndb.QP will appear:
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[WARNING][K+QP] Metallic system
Thanks!
Shudong