Dear Ali, a positive formation energy means that it cost energy to create the defect. A negative one means that the system lower its energy by forming defects --> it will spontaneously form defects.
layla Quoting ali kazempour <kazempoor2000 at yahoo.com>: > > > Ali Kazempour > > Physics department, Isfahan University of Technology > > 84156 Isfahan, Iran. Tel-1: +98 311 391 3733 > > Fax: +98 311 391 2376 Tel-2: +98 311 391 2375 > > --- On Fri, 9/18/09, ali kazempour <kazempoor2000 at yahoo.com> wrote: > > From: ali kazempour <kazempoor2000 at yahoo.com> > Subject: defect formation energy > To: forum at democritos.it > Date: Friday, September 18, 2009, 5:31 AM > > > Hi > for study of point defect ,? i do relax calculation and obtain > positive defect formation energy while by vc-relax i gain negative. ? > what is the difference between positive and negative formation > energy? waht is the physical reasons? > thanks a lot > Ali Kazempour > > Physics department, Isfahan University of Technology > > 84156 Isfahan, Iran. Tel-1: +98 311 391 3733 > > Fax: +98 311 391 2376 Tel-2: +98 311 391 2375 > > > > > > ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program.
