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

Abstract

We present a structural and density functional theory study of the interface of the quasi-twinfree-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.

Thermodynamic constraints and substrate influences on the growth of high-quality Bi2Te3 thin films by pulsed laser deposition

“…It is a layered structured material, where Bi and Te layers are stacked upon each other. While there have been reports on the synthesis of Bi 2 Te 3 thin films by molecular beam epitaxy (MBE), [9][10][11][12][13] the potentials of pulsed laser deposition (PLD) technique, which enables the rapid synthesis of thin films under non-equilibrium conditions, [14][15][16] have not yet been fully investigated. The main culprit for the subpar quality of epitaxially grown Bi 2 Te 3 film roots in the extraordinary high vapor pressure of tellurium, [17][18][19] which requires that Te loss in the deposited films has to be compensated.…”