[salmon-user:00392] sio2 band-gap

[? 雅恬]

Dear SALMON developers,

I am writing to seek your advice regarding a ground-state calculation of bulk SiO₂ (α-quartz) using SALMON.

My calculated fundamental band gap is only about 1.06 eV (direct gap), while the experimental band gap of SiO₂ is known to be around 9 eV. I suspect there might be some mistakes in my input settings, but I have not been able to identify the root cause.

Is there any specific input flag for SiO₂ that I might have missed?

I would greatly appreciate any suggestions or pointers to possible mistakes.

Best regards,

Yatian Ning

[Yamada Shunsuke]

Dear Dr. Yatian Ning,

Thank you for the question. 

Maybe the r-grid is too sparse. Generally, non-orthogonal cell requires relatively dence r-grid for convergence.

For better bandgap, TBmBJ exchenge-correlation functional is more suitable than LDA.

The following link is an example of input file for SiO2 used in a published paper:

https://github.com/SALMON-TDDFT/SALMON-inputs/blob/master/inputfiles/AYamada2024_PhysRevB109_245130/SiO2_ms/gs/SiO2.inp

Sincerely,

Shunsuke Yamada

Kansai Institute for Photon Science, QST, Japan

山田俊介

量子科学技術研究開発機構 関西光量子科学研究所

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差出人: ? 雅恬 <ytni...@outlook.com>
送信日時: 2026年5月29日 18:56
宛先: salmo...@salmon-tddft.jp <salmo...@salmon-tddft.jp>
件名: [salmon-user:00392] sio2 band-gap

 

[宁 雅恬]

Dear Yamada

Thank you for your prompt response. I will follow your advice and carry out the calculation.

Yatian Ning

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发件人: Yamada Shunsuke <yamada....@qst.go.jp>
发送时间: Friday, May 29, 2026 6:35:34 PM
收件人: salmo...@salmon-tddft.jp <salmo...@salmon-tddft.jp>
主题: [salmon-user:00393] Re: sio2 band-gap