Relax again from the last structure and you should get smaller residual stress. Otherwise, increase the cutoffs.<br>Please, read this <br><a href="http://www.quantum-espresso.org/wiki/index.php/Methodological_Background#Stress">http://www.quantum-espresso.org/wiki/index.php/Methodological_Background#Stress</a><br>
<br>Stress smaller than 10 kbar in a solid generally have little effect. <br><br>Eduardo Menendez Proupin<div>Departamento de Química Fisica Aplicada<br>Facultad de Ciencias<br>Universidad Autónoma de Madrid<br>28049 Madrid, Spain<br>
</div><div>Phone: +34 91 497 6706</div><br><br><br>---------- Mensaje reenviado ----------<br>From: bramha pandey <<a href="mailto:pandey.bramha@gmail.com">pandey.bramha@gmail.com</a>><br>To: PWSCF Forum <<a href="mailto:pw_forum@pwscf.org">pw_forum@pwscf.org</a>><br>
Cc: <br>Date: Thu, 22 Mar 2012 19:08:56 +0530<br>Subject: [Pw_forum] Small value of stress at equilibrium (T=0,P=0)<br>Dear all,<br>I am using AlN with zincblede structure using USPP (PBE xc).<br>After completing convergence test of ecut and k-point, i calculated the equilibrium lattice constant(at T=0, P=0).<br>
But i wondered if i put this equilibrium lattice constant in calculation i got, small value of stress(-7.36kbar).<br>
i know this is Pulay stress and think it may be zero (may be i am wrong
if so please correct me) at equilibrium but here it is not the case.<br>i
want to know whether this will affect the other property like bulk
modulus, lattice constant calculation etc at different pressure and
temperature.<br>
How can i fix it.<br>Your valuable comment is highly aappriciable. <br clear="all"><br>-- <br>Thanks and Regards<br>Bramha Prasad Pandey<br>GLA University, Mathura.<br>INDIA.<br clear="all"><br>-- <br><div><br></div>
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