<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;">
<div><font color="#000000"><span style="caret-color: rgb(0, 0, 0);"><img alt="wf.png" src="cid:3EB53083-00E7-4602-8261-421AF470B102"></span></font></div>
<div><br>
</div>
<div>Hi,</div>
<div><br>
</div>
<div>I’m currently computing wave function overlap of some KS-wave functions produced by QE for monolayer MoS2 with SOC enabled. The wave functions are read with HDF5 in Fortran. However, something is bothering me. When computing </div>
<div><br>
</div>
<div>< nk | nk’ >,</div>
<div><br>
</div>
<div>for k = (0.0 , 0.0 , 0.0) and k’ = (1/3, 1/3, 0) in crystal coordinates, and some fixed band, n (I choose the top valence band in this example), I get wildly different values depending on the k-space sampling. I’ve attached a figure, displaying the absolute
value of <span style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0);">< nk | nk’ > for different k-space samplings.</span></div>
<div><span style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0);"><br>
</span></div>
<div><font color="#000000">I would have imagined, that the values of < nk | nk’ > should either be identical or at least look smooth when plotted against the k-space sampling. Can you clarify on this behaviour?</font></div>
<div><span style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0);"><br>
</span></div>
<div><font color="#000000">As a note, the wave function stored in your .hdf5 files have four times the length of the number of planewaves (npw). Therefore, I rearrange the wave function as (Fortran version)</font></div>
<div><font color="#000000"><span style="caret-color: rgb(0, 0, 0);"><br>
</span></font></div>
<div>
<div><font face="Menlo">psi_up_r = psi_k(1 :npw_ ,:),</font></div>
<div><font face="Menlo">psi_up_i = psi_k(npw_+1 :2*npw_ ,:),</font></div>
<div><font face="Menlo">psi_dw_r = psi_k(2*npw_+1 :3*npw_ ,:),</font></div>
<div><font face="Menlo">psi_dw_i = psi_k(3*npw_+1 :4*npw_ ,:),</font></div>
</div>
<div><br>
</div>
<div>where r denotes the real part and vice versa for i. Moreover, I am aware that the G-basis varies for each k-point, and I took care of this as well.</div>
<br>
<div>
<div>Kind regards<br>
<br>
Carl Emil Mørch Nielsen<br>
<br>
---------------------------------------------------------<br>
MSc. Carl Emil Mørch Nielsen<br>
Universität Hamburg<br>
HARBOR, Geb. 610<br>
Luruper Chaussee 149<br>
D-22761 Hamburg<br>
---------------------------------------------------------</div>
</div>
<br>
</body>
</html>