在一维晶格中,若电子波矢忌落在布里渊区边界k=±(nπ/α)时,电子将遭受到与布里渊区边界平行的晶面族的反射,由于在布里渊区边界散射波很强,满足布拉格全彦射的条件,此时微扰论不再适用,须用简并微扰法来处理电子的能带分布。%If electronic wave vector drops on brillouin zone boundary of one-dimensional crystal lattice, elec tron will suffer to the reflection of crystal plane family which is parallel to brillouin zone boundary. Be cause brillouin zone boundary scattered wave is very strong, which meets the conditions of bragg total re flection, at this time, perturbation theory is no longer suitable, and degenerate perturbation theory is used to dealing with electronic band distribution.
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