[Wien] increase band gap with change RMT.

arash bouchani a_bouchani at yahoo.com
Wed Jan 28 17:14:31 CET 2004

```Dear  all  Wein2K Users

We work on electronic structure of InN (III-V group of semiconductors).In literatures there are some different experimental values for energy gap for it.

As follows:

1-                   Eg =0.7ev

2-                   Eg =1.8ev

In computational point of view people have got values like:

1-“emprical pseudopotential calculation” Eg = 2ev

2-“first – principles treatment in the local density approximation”  Eg = 1.3ev

3-                   “ortogonalized linear-combination of atomic orbitals(OLCAO)”  Eg = 1.02ev

4-                   “Linear muffintin-orbitals (LMTO)”  Eg = 0.26ev

5-                   “full-potential linear muffin-tin orbital (FLMTO)”  Eg = -0.26ev

First of all we used LDA and GGA(96) approximations leading to:

1-                   Eg = 0.16 ev (for LDA)

2-                    Eg = 0.17ev (for GGA)

Which are far from  experimental values for this reason I used “Engle&Vosko” approximation

for obtaining energy gap choosing 25 in {case.in0 file}.We obtain “Eg = 0.29975ev” (with  RMT In=1.85 A and RMT N=1.75 A).

As the value of Eg show still there is a discussion for ” Eg” value.

Would you kindly tell me which approximation is suitable for III-V compunds semiconductors specially InN?

As for as know changing the RMT values (whit no error ) in any run(by Engle&Vosko approximation) would not effect in “Eg” values.But I got several values for “Eg” by choosing different values for RMT as follow:

1-  RMT In = 1.85 A

RMT  N = 1.75 A  , ” Eg = 0.29975ev”

2-RMT In = 2 A

RMT N = 1.7 A ,  “Eg = 0.33221ev”

3-RMT In = 2.2 A

RMT N = 1.7 A ,  “Eg = 0.32423ev”

Can you please tell me why we have got different values of Eg for various RMT ?

thankyou -Arash bouchani.

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