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[求助] BiCoO3 P4mm 电极化P的方向？

弱弱的问一下 berry phase计算电极化
BiCoO3 P4mm 电极化的方向为？

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1楼2012-05-08 10:46:16

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9楼: Originally posted by iamikaruk at 2012-05-10 09:21:28:
从对称性角度来说，P4mm的极化方向就只能是方向

请问这怎么理解计算如何操作？
the polarization
should be calculated as a variation via an adiabatic path from
a reference structure with centrosymmetry (no polarizat ion)
or reversed polarization. It is, however, hard to set up such a
path because no ener gy gaps are obtained aroun d a
centrosymmetric structure. To overcome this difficulty, an
external potential is adiabatically applied in such a way that
the insulating electronic structure is retained around the
centrosymmetric structure. Such a potential is arbitrary and
we will see that the following nonlocal potential works well
in the present cases.

An extended adia batic path is thus
constructed, starting from a ferroel ectric state passing the
centrosymmetric structure thr ough a reve rsed sta te by
scaling both the external potential and ionic displacements.