Dynamics of Defects in van der Waals Epitaxy of Bismuth Telluride Topological Insulators

Autor(es)

Morelhao, Sergio L. ^{[1, 2]} ; Kycia, Stefan W. ^[2] ; Netzke, Samuel ^[2] ; Fornari, Celso I. ^[3] ; Rappl, Paulo H. O. ^[3] ; Abramof, Eduardo ^[3]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Phys, BR-05508090 Sao Paulo - Brazil

^[2] Univ Guelph, Dept Phys, Guelph, ON N1G 1W2 - Canada

^[3] Natl Inst Space Res, BR-12227010 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Physical Chemistry C; v. 123, n. 40, p. 24818-24825, OCT 10 2019.
• Citações Web of Science: 0

Resumo

Potential applications in spintronics and quantum information processing have motivated much recent research in epitaxial films of bismuth telluride. This system is also an example of van der Waals (vdW) epitaxy, where the interface coherence between the film and substrate is based on vdW bonds instead of strong ionic or covalent bonds. Because of the weakness of the vdW bonds, the overall quality of the epitaxial films is difficult to control and structural defects are easily introduced with a significant impact on the electronic phase diagram of the epitaxial films. To elucidate the evolution of defects as a function of the growth parameters, we combine nondestructive methods for electrical and structural analysis, as well as to establish intercorrelations between structural features and density of free charge carriers. It clearly shows that point defects and twinned domains favor p-type of charge carriers. Passivation of points defects by formation of metallic bismuth bilayers (BLs) drastically changes the whole film properties. By replacing vdW bonds with weak covalent bonds, the presence of BLs increases the film stiffness, leading to a smaller lattice misfit and a larger lateral lattice coherence length. Charge carriers are flipped to n-type. A few percent of BLs can be a strategy to achieve films with enhanced performance for device applications. (AU)

• Processo FAPESP: 18/00303-7 - Metodologias avançadas para estudo de materiais por difração e espalhamento de raios x
• Beneficiário: Sérgio Luiz Morelhão
• Modalidade de apoio: Bolsas no Exterior - Pesquisa
• Processo FAPESP: 16/22366-5 - Estudo das propriedades do isolante topológico Bi2Te3 crescido por epitaxia de feixe molecular
• Beneficiário: Celso Israel Fornari
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado