The ABINIT Users Mailing List ( CLOSED )

["D. R. Hamann" <drh@bell-labs.com>]

Dear Rongqin,

Can you please attach your .in file for one of these cases?  I'm really not
sure what material you're working with or what the symmetry of the B3
structure is.  I have a feeling that this isn't related to the "Pseudos
for YVO4" thread.

Don Hamann

Wu Rongqin wrote:

Dear all,

    When I tried to do calculations on piezoelectric properties on B3 type lattice, I found that the piezoelectric tensors are all zero! I tried for several different materials in the same B3 structure, and the results are all zero! Why this structure do not possess piezoelectricity? Or my calculation is wrong?

Rongqin Wu

-----Original Message-----
From: Masayoshi Mikami [mailto:mmikami@yk.rim.or.jp] 
Sent: 2004年3月20日 11:46
To: forum@abinit.org
Subject: Re: [abinit-forum] Pseudos for YVO4

Dear Aldo,

Just one more thing: 
In my previous mail, I assumed that your xred in the input 
were already well optimized before trying "optcell 1". 
If not, please try ionmov 2(or 3) without unitcell optimization.

If "optcell 1" (or optcell 2) do not work to get converged 
results, your initial geometry might be far from the plausible
geometry. In such case, you might want to prepare dataset 
with different volumes, and for each volume you could try 
"optcell 3" with "ionmove 2 or 3". (Still, for each volume,
the initial xred should be optimized with ionmov 
before trying "optcell 3")
The equilibirium volume may then be obtained with fitting
such as Murnaghan's equation of state.

Best wishes,
Masayoshi

  

-- 
D. R. Hamann				Phone: 908-582-4454
Director, Theoretical Materials    	Fax:   908-582-4702
  Physics Research (retired)		email: drh@physics.bell-labs.com
Bell Laboratories 
Lucent Technologies
700 Mountain Ave, Room 1D-371
Murray Hill, NJ 07974-0636 USA