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<div class=tx-hanmail-content-wrapper style="font-size: 10pt; font-family: 돋움; color: #333333; line-height: 1.5; background-color: transparent; browser: msie"><P>Dear experts,</P>
<P> </P>
<P>I am going to calculate "spin Chern number" by slightly modifying Wannier90 code.</P>
<P>I was able to calculate "valley Chern number" by simply modifying the Brillouin zone integration part of the anomalous Hall conductivity routine. </P>
<P> </P>
<P>I read referenes on the spin Chern number and WYSV06 [PRB 74, 195118 (2006)] referenced in Berry.f90 code.</P>
<P>Then, I thought that the spin Chern number can be calculated by modifying the routine for Omega_bar, DA and DD terms of Eq. (32) in WYSV06.</P>
<P> </P>
<P>According to Eqs. (32)-(36) in WYSV06, Berry curvature at k is calculated as Omega(k)=SUM_n Omega(k)_n,n with the band index n.</P>
<P>Modifying Omega(k)=SUM_n [sign(Sz)_n Omega(k)_n,n] and integrating Omega(k) over the Brillouin zone, I thought that the spin Chern number can be calculated.</P>
<P> </P>
<P>Then, I modified the routine for Omega_bar, DA and DD terms in Berry.f90. </P>
<P>The diagonal element of each matrix was multiplied by sign(Sz)_n and the trace of the resultant matrix was taken.</P>
<P> </P>
<P>But, I am not so sure. Am I right? I am waiting for any suggestion.</P>
<P>Thank you in advance.</P>
<P> </P>
<P>Lee</P>
<P> </P></div></td></tr>
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