[Pw_forum] Convergence or band-gap problem in orthorhombic CsPbBr3

[Christoph Wolf(신소재공학과)]

Dear Frederico!

The experimental band gap is 2.3-2.4 depending on the method used; my band gap is less than 0.5 eV - rather drastic underestimation. For the orthorhombic phase there are two or three references, but they do not agree well in terms of the location of the gap (sometimes gamma, sometimes R-point) and I am not sure if they applied scissors (it is not stated in the manuscript).

The interesting thing is that the BSE absorption spectrum for the cubic cspbbr3 (a=5.6 A) agrees quite well with my experimental values but the XRD pattern suggests I have o-CsPbBr3. I am following the YAMBO GaSb tutorial (it calculates exactly what I want to calculate); but I am curios where I went wrong with my scf/nscf calculation…

Thank you for your suggestions!

Yours,
Chris

Christoph Wolf
POSTECH university
Dep. Materials Science and Engineering
Chung-am ro 77
Pohang, Gyungbuk
Republic of Korea

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30POSTECH
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