Subject: summary: solid state/band structures

From: [email-masked] (Georg Schreckenbach)
Date: Tue, 30 Sep 1997 13:19:06 -0700

Dear CCL readers,
some two weeks ago, I posted a query about solid state methods.
Here now is the promised summary. Thanx to those who replied.
I didn't get too many answers although they were certainly useful.
I would like to also mention again the older summary on the same
subject, CCL archives, Feb. 20, 96. In a sense, it complements this
new posting. If anybody wants to comment further, please do so!

Best regards, Georg

Here is the original question:

I am interested in solid state (band structure) programs for a research
proposal that I am just starting to think about.

A CCL archive search shows that this question pops up regularly in
one form or another. The last time was just a few days ago! However, the
same archive search revealed that there are, unfortunately, mostly
questions, and not many answers: The only related summary that I
could find is dated 20 Feb. 1996.
   Some of the relevant programs mentioned briefly in this summary are:
- ADF-BAND (http://www.scm.com/)
- WIEN97 (http://www.tuwien.ac.at/theochem/wien97/)
- and then there are the Car-Parinello type codes, including "PAW" of P.
Blochl et al.

So far for the background, and here are my questions in more detail.

Since this is a very early state of a possible future project, I am trying
to gain a broad overview. Basically what I want to learn is the state
of the art in the field of doing solid state calculations from a chemical
point of view. My questions are, e.g.:
- What kinds of programs are out there? (relevant literature?)
- What methods do they use (e.g., plane waves or other basis sets;
DFT or ab initio -- I am not interested in semiempirical approaches in the
moment). Which method might be superior over another?
- What functionality is available (ECPs or other ways to
include relativistic effects, geometry optimizations, properties ...)?
- General experience of users of, e.g., the mentioned programs
(source code available?, numerical stability, user friendliness,
number of bugs that one runs into, cost ...)
- Any other info that you would deem useful.

1) Reply by Keith Refson

Georg Schreckenbach writes:

 > A CCL archive search shows that this question pops up regularly in
 > one form or another. The last time was just a few days ago! However, the
 > same archive search revealed that there are, unfortunately, mostly
 > questions, and not many answers: The only related summary that I
 > could find is dated 20 Feb. 1996.
 >    Some of the relevant programs mentioned briefly in this summary are:
 > - ADF-BAND (http://www.scm.com/)
 > - WIEN97 (http://www.tuwien.ac.at/theochem/wien97/)
 > - and then there are the Car-Parinello type codes, including "PAW" of P. Bl=
 > =F6chl
 > et al.

A few other programs to add to your list:

CRYSTAL (http://www.dl.ac.uk/TCSC/Software/CRYSTAL/).  This does
periodic Hartree-Fock calculations on solids using standard Gaussian
basis sets.  No forces or geometry optimization.

CASTEP (http://www.msi.com/info/products/modules/CASTEP.html,
        http://www.tcm.phy.cam.ac.uk/castep/)

 - Unfortunately now available only to but from MSI, this is Mike
   Payne's plane-wave pseudopotential code.

   Also from MSI, the Cornell PWPP code:
PLANE_WAVE (http://www.msi.com/info/products/modules/I2_QP.html)

CETEP: The parallel version of CASTEP used by the UK Car-Parrinello
   consortium.  Collaboration may be possible.
   (http://www.dl.ac.uk/TCSC/projects/UKCP/ukcp.html)

VASP ( http://tph.tuwien.ac.at/~vasp/)
   The Vienna ab-initio simulation package.  One of the best
   and most highly developed plane-wave pseudopotential codes.
   Not free but the price is modest.

There's Ali Alavi's FEMD

The most widely avaliable LAPW code is WIEN97 which you already have.
The other thing to mention is Methfessel's FP-LMTO program.  I don't
have a WWW address, but I may be able to dig out a literature reference.

There are also other 3 or 4 other plane-wave pseudopotential codes
which aren't generally avaliable - Parrinello's group amongst others.

 >
 >  Basically what I want to learn
 > is the state of the art in the field of doing solid state
 > calculations from a chemical point of view.

You could do a lot worse than look at the UKCP publications list and
work in progress, see the URL above.

 > - What kinds of programs are out there? (relevant literature?)

You should find this from the URLs listed.

 > - What methods do they use (e.g., plane waves or other basis sets;

Most of the ones I listed are plane-wave + pseudopotential codes and
use DFT.  The exception you listed was WIEN97 which uses the LAPW
basis set.  I believe there is a version which uses pseudopotentials
but it's primarily an all-electron method.  The exception in my list
is CRYSTAL which is a Hartree-Fock program using the usual Gaussian
basis sets.

 > DFT or ab initio

Be aware that physicists don't share the chemists' view of using
ab-initio to refer only to Harfree Fock and methods based on it.
DFT is definitely ab-initio in the physics lexicon.

 >  Which method might be superior over another?

DFT is always superior [ :) ].  This is more seriously true
in the solid state world (a) because no periodic program implements
any higher-level of Hartree-Forck - not even MP2.  The best that can
be done is the non-self-consistent density-functional correlation
correction in CRYSTAL. (b) Hartree-Fock gets the metallic state so
badly wrong that there's no point in even trying, so it has a bad name
in the physics world.

 > - What functionality is available (ECPs or other ways to include
 > relativistic effects,

CRYSTAL has ECPs.  All plane-wave codes use pseudopotentials, which
in the fashionable form are ab-initio, (sometimes) norm-conserving
and nodeless.  I can't remember whether WIEN97 handles relativistic
effects or not but there is an experimental version which uses
pseudopotentials.

 > geometry optimizations,

All but CRYSTAL have forces and do geometry optimizations + molecular
dynamics.  VASP has a pretty extensive list of properties, but you'll
have to check on the web sites for the rest.

 > - General experience of users of, e.g., the mentioned programs
 > (source code available?, numerical stability, user friendliness, number of
 > bugs that one runs into, cost ...)

If you make up a table I can add comments on those I know about.  FYI
the UKCP is currently running a comparitive evaluation of FEMD,
CASTEP/CETEP and VASP.  I don't know whether the results are being
made public but I will try to determine that in our meeting on Monday
and let you know if it's allowed.  There's certainly a comprehensive
"features" list for them.

At the moment most of the excitement is still with the plane-wave
pseudopotential methods because of the O(N**2) scaling with system
size.  O(N) methods are under development (including the UCKP code)
but I don't know of any which are in a useable state for general
research as yet.

There are also many post-LDA developments foing on such as SIC, LDA+U,
exact exchange and others which I can't recall at the moment which all
promise a much better approximation to "true dft" and hopefully to
reality.  I'm sure we will find out which of them deliver in the next
few years.

Hope this info is helpful.

sincerely

Keith Refson
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2) Another reply by Keith Refson:

Ome more program I nearly for got - "fhi93cp" which is Matthias
Scheffler's plane-wave pseudopotential code.  It's available from the
Computer Physics Communications program library: - see

http://www.cpc.cs.qub.ac.uk/cpc/

Keith Refson

3) Yet another reply by Keith Refson, answering a specific
question of mine:

I have talked to David Sherman of Bristol Uni who has tried out
ADF-BAND and who spoke highly of its useability.  However as far as I
know it can not calculate forces and therefore can't do geometry
optimizations which rather rules it out for most things I'd want it for.

4) From: [email-masked] (John Nicholas)
(I asked him about the results of a similar posting earlier
on the CCL)

Georg, I'm not sure how easy it would be to get
all the replies together, but I can pretty much tell
you what's available:

Crystal (RHF and DFT), DSolid, CASTEP, Bloch-Demon, VASP, QUEST,
DECAPO are all availble in various forms. I think the plane
wave methods have such an advatage (speed) over the other
basis-sets that they are far preferred.

Also amsterdam-DFT.

Regards, John

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(End of summary)

--
==============================================================
Dr. Georg Schreckenbach           Tel:     (USA)-505-667 7605
Theoretical Chemistry T-12        FAX:     (USA)-505-665 3909
M.S. B268, Los Alamos National      E-mail:  [email-masked]
Laboratory, Los Alamos, New Mexico, 87545, USA
Internet:    http://www.t12.lanl.gov/~schrecke/
==============================================================

---

From: Jan Gryko <[email-masked]>
Date: Tue, 30 Sep 1997 16:45:45 -0500 (CDT)

Does anyone have experience runing typical MD or DFT
  code under Linux on Alpha system? Is it true that 
  Alpha system with IDE hard drive is unstable under Linux?
  (There are such rumors...)

  I will summarize answers to the list.

  Thanks,

  Jan Gryko
  Jacksonville State Univ.