<div dir="ltr"><p class="MsoNormal">Dear  QE user,</p>

<p class="MsoNormal" style="margin-bottom:0.0001pt">I am a new user of QE. I  want to calculate the band structure of
bi-layer graphene  by employing external
electric field. <span style="font-family:Arial,sans-serif;background-image:initial;background-repeat:initial">I have done the <span id="6dfdc767-fe8c-4663-bbc5-e2207375e170" class="GINGER_SOFTWARE_mark">scf</span> calculations without electric field, then
again did the <span id="71e10364-a1b1-47b6-8b18-966c4863293b" class="GINGER_SOFTWARE_mark">scf</span> calculation with an electric field included in the z-direction</span>
(<span style="font-family:'Courier New'">efield_cart (1) = 0. d0, efield_cart
(2<span id="c2180c77-6575-4205-a2a6-308150d72e5c" class="GINGER_SOFTWARE_mark">)</span>=0<span id="0eaa5cc7-558a-4ba0-96e8-c5ef08689377" class="GINGER_SOFTWARE_mark">.</span>d0,</span></p>

<p class="MsoNormal" style="margin-bottom:0.0001pt"><span style="font-family:'Courier New'">              efield_cart<span id="947bfbda-0337-49fc-abfc-d1108f2874b4" class="GINGER_SOFTWARE_mark">(</span>3) = 0.001d0,</span><span style="font-family:Arial,sans-serif;background-image:initial;background-repeat:initial">). Then
I have done the <span id="3f118150-170d-462c-b3ac-ccfb20e6bbaf" class="GINGER_SOFTWARE_mark">nscf</span> calculations with electric field. Now I have to calculate
the <span id="1b3329a2-74e9-4ed1-b223-f612d6a1cccc" class="GINGER_SOFTWARE_mark">bands</span> calculation. But I am confused about the <span id="5503eebc-e7db-4aad-aea8-686cd190d669" class="GINGER_SOFTWARE_mark">step</span>. Now my question is<span id="2620d6ab-0e46-4e32-8872-ec4c32e05743" class="GINGER_SOFTWARE_mark"> –</span></span><span style="font-family:'Courier New'"></span></p>

<p class="" style><span style="font-family:Wingdings">Ø<span style="font-size:7pt;font-family:'Times New Roman'">                 1)  </span></span><span style="font-family:Arial,sans-serif;background-image:initial;background-repeat:initial">Is it necessary to optimize (<span id="2b22d4d5-7f2d-4b11-8b3b-84b68e63d321" class="GINGER_SOFTWARE_mark">vc</span>-relaxed) the
structure with an electric field before performing the <span id="12053d30-edc4-47a1-80e1-8f8da874a9c0" class="GINGER_SOFTWARE_mark">scf</span> calculation?</span></p>

<p class="" style><span style="font-family:Wingdings">Ø<span style="font-size:7pt;font-family:'Times New Roman'">                 2) </span></span><span style="font-family:Arial,sans-serif;background-image:initial;background-repeat:initial">In the band calculation am I include the ‘</span><span style="font-family:'Courier New'"><span id="b4c0835f-3857-4a87-a79a-54ce78a0f2df" class="GINGER_SOFTWARE_mark">lelfield</span> =<span id="e0cda76c-d4d0-48ae-a23e-d441752c5aa6" class="GINGER_SOFTWARE_mark"> .</span><span id="abbb9b97-3ca2-40c9-82b6-6d80d3aeb457" class="GINGER_SOFTWARE_mark">true</span>.’ option?</span><span style="font-family:Arial,sans-serif;background-image:initial;background-repeat:initial"></span></p>

<p class=""><span style="font-family:Arial,sans-serif;background-image:initial;background-repeat:initial"> </span></p>

<p class=""><span style="font-family:Arial,sans-serif;background-image:initial;background-repeat:initial">Could anyone please guide me and share their experience?</span></p>

<p class=""><span style="font-family:Arial,sans-serif;background-image:initial;background-repeat:initial">I am waiting for positive response</span></p>

<p class=""><span style="font-family:Arial,sans-serif;background-image:initial;background-repeat:initial">  Thanking
you in advance.</span></p>

<p class=""><span style="font-family:Arial,sans-serif;background-image:initial;background-repeat:initial"> </span></p>

<p class=""><span style="font-family:Arial,sans-serif;background-image:initial;background-repeat:initial">Sincerely </span></p>

<p class=""><span style="font-family:Arial,sans-serif;background-image:initial;background-repeat:initial"><span id="bf4d095b-4ecb-4546-ab96-e4bae3b7a3ca" class="GINGER_SOFTWARE_mark">barnali</span></span></p></div>