Dear Young-Su,<div><br></div><div>thank you for your replay.</div><div><br></div><div>if i take the previous unit cell: </div><div><br></div><div>----->a</div><div>| o o | o o|</div><div><br></div><div> A1 B1 A2 B2</div>
<div><br></div><div> 2 1 2 1</div><div><br></div><div>the first wannier function is located to B1 and the second one is located to A2.</div><div>this information i was missing to report/say in my previous email.</div>
<div><br></div><div>Following your suggestion then:</div><div><br></div><div> 0 0 0 2 1 0.222025 0.000000</div><div> 0 0 0 1 2 0.222025 0.000000</div><div><br></div><div>is meaning that hopping between B1 and A2 is 0.222025;</div>
<div><br></div><div> 1 0 0 2 1 0.203502 0.000000</div><div><br></div><div>is meaning that hopping between A2 and B2 is 0.203502;</div><div><br></div><div> -1 0 0 1 2 0.203502 0.00000</div>
<div><br></div><div>is meaning that hopping between B1 and A1 is 0.203502</div><div><br></div><div>This makes sense to me.</div><div><br></div><div>cheers,</div><div><br></div><div>Gianluca Giovannetti</div><div><br></div>
<div><br></div><div> </div><div><br></div><div><br></div><span class="Apple-style-span" style="font-family: arial, sans-serif; font-size: 11px; border-collapse: collapse; color: rgb(80, 0, 80); "><div><p class="MsoNormal" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">
<br></p><p class="MsoNormal" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-size: small; ">2011/3/7 Young-Su Lee <span dir="ltr"><<a href="mailto:lee0su@kist.re.kr">lee0su@kist.re.kr</a>></span></span></p>
</div></span><div><div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"><div style="background:#ffffff"><div><div class="im">
<p class="MsoNormal" style="margin:0cm 0cm 0pt"><span lang="EN-US" style="font-size:10pt;color:#1f497d">Dear Gianluca Giovannetti,</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 0pt"><span lang="EN-US" style="font-size:10pt;color:#1f497d"> </span></p>
<p class="MsoNormal" style="margin:0cm 0cm 0pt"><span lang="EN-US" style="font-size:10pt;color:#1f497d">You can interpret hr.dat using the five indices preceding the H matrix element:</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 0pt"><span lang="EN-US" style="font-size:10pt;color:#1f497d"> i j k m n indicates H element between the m_th WF at the final center and the n_th WF at (the final center + (i,j,k) lattice vector) </span><span style="font-size:10pt;color:#1f497d">–<span lang="EN-US"> please someone correct me, if this is wrong.</span></span></p>
<p class="MsoNormal" style="margin:0cm 0cm 0pt"><span lang="EN-US" style="font-size:10pt;color:#1f497d"> </span></p>
<p class="MsoNormal" style="margin:0cm 0cm 0pt"><span lang="EN-US" style="font-size:10pt;color:#1f497d">The WF indices follow the order in the *wout file.</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 0pt"><span lang="EN-US" style="font-size:10pt;color:#1f497d">The final center does not have to reside in the home cell, as you</span><span style="font-size:10pt;color:#1f497d">’<span lang="EN-US">ve already noticed from the WF at A2.</span></span></p>
<p class="MsoNormal" style="margin:0cm 0cm 0pt"><span lang="EN-US" style="font-size:10pt;color:#1f497d">If your first WF is at A2 and the second one is at B1</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 0pt"><span lang="EN-US" style="font-size:10pt;color:#1f497d"> </span></p>
<p class="MsoNormal" style="margin:0cm 0cm 0pt"><span lang="EN-US" style="font-size:10pt;color:#1f497d">1 0 0 2 1 : btw B1 and A3</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 0pt"><span lang="EN-US" style="font-size:10pt;color:#1f497d">1 0 0 1 2 : btw A2 and B2</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 0pt"><span lang="EN-US" style="font-size:10pt;color:#1f497d">-1 0 0 2 1 : btw B1 and A1</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 0pt"><span lang="EN-US" style="font-size:10pt;color:#1f497d"> </span></p>
<p class="MsoNormal" style="margin:0cm 0cm 0pt"><span lang="EN-US" style="font-size:10pt;color:#1f497d">If you want to move the WF at A2 to A1, use translation_centre_frac = 0.5, 0.5, 0.5, then all the WFs will be inside your home cell (translate_home_cell only translates centers without modifying hr.dat). I guess this is less confusing.</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 0pt"><span lang="EN-US" style="font-size:10pt;color:#1f497d"> </span></p>
<p class="MsoNormal" style="margin:0cm 0cm 0pt"><span lang="EN-US" style="font-size:10pt;color:#1f497d">Hope this helps.</span></p>
<p class="MsoNormal" style="margin:0cm 0cm 0pt"><span lang="EN-US" style="font-size:10pt;color:#1f497d"> </span></p>
<p class="MsoNormal" style="margin:0cm 0cm 0pt"><span lang="EN-US" style="font-size:10pt;color:#1f497d">Young-Su </span></p>
<p class="MsoNormal" style="margin:0cm 0cm 0pt"><span lang="EN-US" style="font-size:10pt;color:#1f497d"> </span></p><br><br><br></div><b> ----- Original Message -----</b></div>
<div style="padding-left:10px;margin-left:5px;border-left:#000000 2px solid;margin-right:0px"><div class="im">From: Gianluca Giovannetti <br>To: <a href="mailto:wannier@quantum-espresso.org" target="_blank">wannier@quantum-espresso.org</a><br>
</div><div><div></div><div class="h5">Date: 2011-03-07 17:15:40<br>Subject: [Wannier] understanding the output of Wannier90<br>Dear All,
<div><br></div>
<div>i`m having a problem in understanding the output of wannier90 (file hr .dat).</div>
<div><br></div>
<div>i have made a calculation for a molecular crystal.</div>
<div><br></div>
<div>the unit cell consists of molecular sites (A and B) along the stacking direction a (with a lattice vector) as illustrated in the following:</div>
<div><br></div>
<div>-----> a</div>
<div><br></div>
<div>|o ? o | o ? o | ......</div>
<div>?A ? B ?A ?B</div>
<div><br></div>
<div>(here i`m plotting schematically two unit cells)</div>
<div><br></div>
<div>Let label the molecules in this way:</div>
<div><br></div>
<div>
<div>-----> a</div>
<div><br></div>
<div>|o ? ?o | o ? ?o | ......</div>
<div>?A1 B1 A2 B2</div>
<div><br></div>
<div>now the bonds B1-A2 are shorter while bonds A2-B2 are longer (the system is dimerized).</div>
<div><br></div>
<div>the HOMOs (highest occupied molecular orbitals) of the two molecules A,B contained in the unit cell hybridize, giving rise to bonding and antinbonding bands around the Fermi level. then at Fermi level i have two states.</div>
</div>
<div><br></div>
<div>the calculations performed with PW and W90 looks fine and the agreement of PW and W90 bands is good.</div>
<div><br></div>
<div>once i plot using xcrystalden the Wannier functions of the such states at Fermi one is located at A2 and the other one is located to B1 (basically one is in the unit cell and the other one is located at the NN unit cell along a).</div>
<div><br></div>
<div>now i go to look at the hr.dat file and i find:</div>
<div><br></div>
<div>??? 0 ? ?0 ? ?0 ? ?1 ? ?1 ? ?3.334228 ? ?0.000000</div>
<div>?? ?0 ? ?0 ? ?0 ? ?2 ? ?1 ? ?0.222024 ? ?0.000000</div>
<div>?? ?0 ? ?0 ? ?0 ? ?1 ? ?2 ? ?0.222024 ? ?0.000000</div>
<div>?? ?0 ? ?0 ? ?0 ? ?2 ? ?2 ? ?3.334221 ? ?0.000000</div>
<div><br></div>
<div>
<div>?? ?1 ? ?0 ? ?0 ? ?1 ? ?1 ? ?0.000243 ? ?0.000000</div>
<div>?? ?1 ? ?0 ? ?0 ? ?2 ? ?1 ? ?0.203498 ? ?0.000000</div>
<div>?? ?1 ? ?0 ? ?0 ? ?1 ? ?2 ? ?0.000122 ? ?0.000000</div>
<div>?? ?1 ? ?0 ? ?0 ? ?2 ? ?2 ? ?0.000242 ? ?0.000000</div></div>
<div><br></div>
<div>
<div>?? -1 ? ?0 ? ?0 ? ?1 ? ?1 ? ?0.000243 ? ?0.000000</div>
<div>?? -1 ? ?0 ? ?0 ? ?2 ? ?1 ? ?0.000122 ? ?0.000000</div>
<div>?? -1 ? ?0 ? ?0 ? ?1 ? ?2 ? ?0.203498 ? ?0.000000</div>
<div>?? -1 ? ?0 ? ?0 ? ?2 ? ?2 ? ?0.000242 ? ?0..000000</div>
<div><br></div>
<div>i have some doubts in understanding the hopping parameters.</div>
<div><br></div>
<div>i see the kinetic terms are different?0.222024/0.203498 as one would expect in a dimerized structure. this is fine.</div>
<div><br></div>
<div>the values 3.334228 are the on-site energies of the tight-binding problem.</div>
<div><br></div>
<div>my problem is the following.</div></div>
<div>is 0.222024 referring to the the hopping between A1 and B1 (also between A2 and B2) ?or between B1 and A2?</div>
<div><br></div>
<div>because the Wannier functions plotted in real space are sitting between adjacent different unit cells i would expect 0.222024 referring to?hopping between?B1 and A2 and 0.203498??referring to?hopping between?A1 and B1 (also between A2 and B2).</div>
<div>then at smaller distances would correspond larger hoppings and at larger distances?would correspond smaller?hoppings.</div>
<div><br></div>
<div>could you please confirm this way to interpret the file hr.dat? :-)</div>
<div><br></div>
<div>i thank you in advance for our time.</div>
<div><br></div>
<div>cheers,</div>
<div><br></div>
<div>Gianluca Giovannetti</div></div></div></div></div><br>
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