Results

GaInAs

 

We look at unit cells extended in the (110) direction of GaAs stacked on top of InAs. We use 6,10, and 20 layers of GaAs on top of respectively 6,10, and 20 layers of InAs. A 1x4x4 Monkhorst-Pack mesh is used for the k-point sampling.

 

 

 

For the 6-layer system, we can see that all methods perform fairly well. The Broyden method “ br” shows early deficiencies. The “krk” signifies that the Pulay_Kerker mixing is used: “tf” Pulay_Thomas-Fermi and “dir” signifies the direct minimization method. “mg” signifies the Mauri-Galli functional is used for the electronic minimization and “gcg” signifies the Grassmann conjugate gradient algorithm.

 

 

 

The convergence of the Broyden method shows worsening. There is not a significant difference between the other methods. The “dir.gcg” and the “tf.mg” methods appear to be the best, but the Pulay-Kerker and Pulay-Thomas-Fermi mixng with the GCG minization do not differ significantly.

 

 

 

 

 Again the “dir.gcg” and the “tf.mg” methods converge at almost the exact same time. We have dropped the Broyden scheme as it had already proven to be insufficient in the 10-layer system.