For some materials, the global crystal structure is unchanged but there is a local symmetry breaking. Could anybody advise what is the effect of such local symmetry breaking on the electronic band structure and band topology? What type of theoretical method can use short-range local low crystal symmetry and long-range higher crystal symmetry to calculate the electronic band structures? I know DFT cannot do such type of theoretical work and may only consider the long-range crystal symmetry. Any advice is highly appreciated!
Hello Qiang,
Certain aspects of this problem can be studied even in DFT by using a large supercell, in which each individual unit cell has small symmetry-breaking distortions. These distortions are not long-range ordered so they average to approximately zero over the whole structure. The effects on the band structure can be very significant, such as triggering a Jahn-Teller style gap opening in materials which have no DFT band gap in their experimentally determined high-symmetry structure. Alex Zunger's group has done some good work on this topic in recent years; if you are not familiar with those papers, they might offer some ideas on how to proceed. Article A polymorphous band structure model of gapping in the anti-f...
https://www.nature.com/articles/s41467-019-09698-6
Steven Hartman Thanks for your answer and very valuable advice! I am reading the paper you recommended. Merry Christmas to you and your family!
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