Piezoelectric tunability and topological insulator transition in a GaN/InN/GaN quantum-well device

Using an 8-band k center dot p model it is demonstrated through the combination of strain and piezoelectricity that increasing the InN quantum-well thickness of a GaN-InN-GaN device changes the InN material from a positive bandgap semiconductor to a topological insulator (negative bandgap). Moderate strain tuning of a four monolayer InN layer for a GaN-InN-GaN device reveals a giant (one order of magnitude) tuning of current-voltage characteristics. It is verified that piezoelectricity plays an important role in controlling electron transport through the InN layer.

Automated summary

By utilizing an 8-band k center dot p model, it has been shown that increasing the thickness of the InN quantum well in a GaN-InN-GaN device can change the bandgap properties of InN material and significantly tune the current-voltage characteristics. It is confirmed that piezoelectricity plays a crucial role in controlling electron transport through the InN layer.