Diffusion of Ga and As ions in simulated liquid gallium arsenide was studied using a model containing 3000 ions, and periodic boundary conditions. The diffusion constant was calculated between 5000 and 1400K (table 26). Results for liquid with a density of 5.3176g/cm3 showed that the temperature dependence of the diffusion constant obeyed an Arrhenius law at relatively low temperatures above the melting point, and exhibited a power-law, (T-Tc)γ;, at higher temperatures. Upon cooling the system from relatively high temperatures to low temperatures, a cross-over from non-Arrhenius to Arrhenius dynamics in the liquids was found, corresponding to a transition from fragile to strong liquid behaviour. The glass-phase transition-temperature was found to be about 1050K.

Molecular Dynamics Simulation of Diffusion in Liquid Gallium Arsenide. Thu, H.T.T., Hoang, V.V.: Computational Materials Science, 2010, 49[4], S221-4

Table 26

Diffusivity in liquid GaAs

 

Temperature (K)

Diffusant

D (cm2/s)

1400

Ga

0.05 x 10-5

1400

As

0.05 x 10-5

1500

Ga

0.10 x 10-5

1500

As

0.10 x 10-5

1700

Ga

0.34 x 10-5

1700

As

0.33 x 10-5

1800

Ga

0.56 x 10-5

1800

As

0.58 x 10-5

2000

Ga

1.05 x 10-5

2000

As

1.09 x 10-5

2500

Ga

2.80 x 10-5

2500

As

2.79 x 10-5

2800

Ga

4.16 x 10-5

2800

As

4.11 x 10-5

3000

Ga

4.89 x 10-5

3000

As

4.99 x 10-5

3500

Ga

7.29 x 10-5

3500

As

7.36 x 10-5

3800

Ga

8.41 x 10-5

3800

As

8.87 x 10-5

4000

Ga

9.51 x 10-5

4000

As

9.55 x 10-5

4500

Ga

12.22 x 10-5

4500

As

12.02 x 10-5

4800

Ga

14.26 x 10-5

4800

As

13.10 x 10-5

5000

Ga

13.98 x 10-5

5000

As

14.07 x 10-5