<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><br></div><div>You can sample the BZ choosing an appropriate set of k-points inside a primitive cell of the reciprocal lattice. The simplest one, using crystal coordinates, is just a cube of side 1 with a corner in the origin. Then, along each side of the cube you can chose a different grid spacing, which should be inversely proportional to the length (in cartesian metrics) of the corresponding crystal vector, in order to perform an optimal sampling (at least, in my opinion).</div><div><div><div>Then you can bring all k-points back to the 1st BZ, reduce them to an irreducible set using symmetry, and transform them to cartesian coordinates, if you want.</div><div>Perhaps there are other better ways to sample the BZ, but this is the simplest I have in mind and it should be the one used in PWscf (see PW/kpoint_grid.f90).</div><div><br></div><div>HTH</div><div><br></div><div>GS</div><div><div><div><br><div><div>Il giorno 05/mag/2011, alle ore 10.01, germaneau ha scritto:</div><br class="Apple-interchange-newline"><blockquote type="cite"><br><p>Dear Gabriele,</p><p>I have calculated the reciprocal lattice vectors.<br></p><p>I don't get why you said that is the only thing missing.</p><p>I have to select k-vectors from the 1st Brillouin zone only, and that's what I can't figure out.</p><p>Thank you,</p><p> Eric.</p><div> <br class="webkit-block-placeholder"></div><br><br><br>------------------ ÔʼÓʼþ ------------------<br>>From: Gabriele Sclauzero <<a href="mailto:sclauzer@sissa.it">sclauzer@sissa.it</a>><br>>Reply-To: PWSCF Forum <<a href="mailto:pw_forum@pwscf.org">pw_forum@pwscf.org</a>><br>>To: PWSCF Forum <<a href="mailto:pw_forum@pwscf.org">pw_forum@pwscf.org</a>><br>>Subject: Re: [Pw_forum] grid of spacing k-vectors<br>>Date: Thu, 5 May 2011 10:01:52 +0200<br>><br><br>Dear ric,<div><br></div><div> I would say that, for a uniformly spaced grid of k-points, specifying the number of k-points is equivalent to specify the grid spacing (along each basis vector of the reciprocal space independently). Since you know the direct lattice vectors, then you can get the length of the reciprocal lattice vectors, which is the only thing missing.</div><div><br></div><div><br></div><div><div><div>Gabriele</div><div><br></div><div><br></div><div>Il giorno 05/mag/2011, alle ore 16.14, Eric Germaneau ha scritto:</div><br class="Apple-interchange-newline"><blockquote type="cite">
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Dear all,<br>
<br>
I'm wondering whether it's possible to generate k-vectors for the
Brillouin sampling using <br>
a grid of spacing instead of a number of vectors.<br>
Thank you,<br>
<br>
ric.<br>
<br>
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<span class="Apple-style-span" style="border-collapse: separate; font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div><span class="Apple-style-span" style="color: rgb(126, 126, 126); font-size: 16px; font-style: italic; "><br class="Apple-interchange-newline">¡ì Gabriele Sclauzero, EPFL SB ITP CSEA</span></div><div><font class="Apple-style-span" color="#7E7E7E"><i> PH H2 462, Station 3, CH-1015 Lausanne</i></font></div></span>
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