Modification of the van der Waals interaction at the Bi2Te3 and Ge(111) interface

We present a structural and density-functional theory study of the interface of the quasi-twin-free grown three-dimensional topological insulator Bi2Te3 on Ge(111). Aberration-corrected scanning transmission electron microscopy and electron energy-loss spectroscopy in combination with first-principles calculations show that the weak van der Waals adhesion between the Bi2Te3 quintuple layer and Ge can be overcome by forming an additional Te layer at their interface. The first-principles calculations of the formation energy of the additional Te layer show it to be energetically favorable as a result of the strong hybridization between the Te and Ge.

Automated summary

The study demonstrates that the weak van der Waals adhesion between Bi2Te3 and Ge can be overcome by forming an additional Te layer at their interface. First-principles calculations show that the formation of the additional Te layer is energetically favorable due to the strong hybridization between Te and Ge.