Silicon Based Life FormsSilicon Based Life Forms

Peter BalloPeter Ballo

Cluster technique

Lattice constant

Bulk modulus

Cohesive energy

Vacancy formation energy

DLTS spectroscopy

5.43 5.44 5.45 5.46 5.47 5.48-9644.6

-9644.5

-9644.5

-9644.4

-9644.4

-9644.3

-9644.3

-9644.2

Ene

rgy

(eV

)

Lattice constant (A)

Lattice constant

a=5.44 Å

Bulk modulus

5.43 5.44 5.45 5.46 5.47 5.48-9644.6

-9644.5

-9644.5

-9644.4

-9644.4

-9644.3

-9644.3

-9644.2

Ene

rgy

(eV

)

Lattice constant (A)

2

2

0 dV

EdVB

GPaB 1.96

Cohesive energy

Cluster Energy (eV)

Si9H15 -954,36

Si102H82 -9644.87

Element Lattice energy (eV)

Silicon -83.84

Hydrogen -13.32

eVEc 66.4 V-79.17738e)(1 SiE

)(1 SiEEE Lc

Ecoh=-(Total energy of one free atom – Total energy of cluster/Number of atoms)

Vacancy formation energy

Lv EnEnEE )1()(

eVEv 30.3

Method ao(Å) B(GPa) Ec(eV) Ev(eV)

cluster 5.44 96.1 -4.66 3.30

ab initio 5.39(a) 100.0(a) -4.51(b) 3.38(c)

experiment 5.43(d) 98.8(d) -4.63(d)

Summary

(a) Pesola, J.von Boehm, T.Mattila, and R.M.Nieminen, Phys.Rev.B 60,11 449 (1998). (b) X.-P. Li, D.M.Ceperley, and R.M.Martin, Phys.Rev.B 44, 10 929 (1991). (c) S.J.Clark and G.J.Ackland, Phys.Rev.B 48, 10 899 (1993). (d) Ch. Kittel, Introduction to Solid State Physics (Wiley, New York, 1996).

1,0 1,5 2,0 2,5 3,0 3,5 4,0-0,05

0,00

0,05

0,10

0,15

0,20

0,25

0,30E

nerg

y (e

V)

Distance (A)

Korekčná funkcia v MNDOKorekčná funkcia v MNDO

DO

S (

arb.

uni

ts)

Energy (eV)

Oxygen defectP.Ballo and L.Harmatha, Phys.Rev.B 68, 153201 (2003).

eVEE v 6.1 eVEE v 05.0

B

O

C

A

defaults used first point

MOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDEN

A

B

C

O

defaults used first point

MOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDENMOLDEN

A centrum H centrumA centrum H centrum

E(NO)=-2.87eV E(2NO)=-5.52eV