Tailoring topological states of core–shell nanoparticles

• Published in: Physica. E, Low-dimensional systems & nanostructures Vol. 136; p. 115000
• Main Authors: Martínez-Strasser, Carolina, Baba, Yuriko, Díaz-Fernández, Álvaro, Domínguez-Adame, Francisco
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2022
• Subjects: Core–shell nanoparticles; Surface states; Topological insulator; Topological insulator; Core–shell nanoparticles; Surface states
• ISSN: 1386-9477; 1873-1759
• DOI: 10.1016/j.physe.2021.115000

In this work we investigate novel spherical core–shell nanoparticles with band inversion. The core and the embedding medium are normal semiconductors while the shell material is assumed to be a topological insulator. The envelope functions are found to satisfy a Dirac-like equation that can be solved in a closed form. The core–shell nanoparticle supports midgap bound states located at both interfaces due to band inversion. These states are robust since they are topologically protected. The energy spectrum presents mirror symmetry due to the chiral symmetry of the Dirac-like Hamiltonian. As a major result, we show that the thickness of the shell acts as an additional parameter for the fine tuning of the energy levels, which paves the way for electronics and optoelectronics applications. •The paper stresses the tuning possibilities of spherical core–shell nanoparticles.•The nanoparticles show band inversion and topological insulator interfaces.•The thickness of the shell acts as a parameter for the tuning of the energy levels.•These results paves the way for electronics and optoelectronics applications.