(416e) Electromagnetic Coupling and Transport in a Topological Insulator–Graphene Heterostructure | AIChE

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(416e) Electromagnetic Coupling and Transport in a Topological Insulator–Graphene Heterostructure

Authors 

Munoz, E. - Presenter, Pontificia Universidad Catolica de Chile
The combination of different materials in the form of heterostructures [1] is our modern quest to search for novel properties that emerge beyond the trivial superposition of those of their individual parts. This search is of great interest not only from a fundamental perspective, since exciting new phenomena may be observed, but also to engineer materials for applications in novel devices. Among the different emerging phenomena in heterostructures, electromagnetic effects are highly relevant for the transmission and storage of energy and information. In this context, the control of electronic transport properties is of fundamental importance. The discovery of novel materials with nontrivial topological properties, such as topological insulators (TIs) [1,3,4] and Dirac and Weyl semimetals [2], has introduced a plethora of new phenomenology. In particular, the existence of surface chiral states makes them excellent potential candidates for applications in quantum information technologies and thermoelectrics [2,3,4]. In addition, the so-called magnetoelectric polarizability (MEP) [1] that locally modifies the constitutive relations between the electromagnetic fields in TIs provides new opportunities to control the magnetoelectric response in such systems. Even though these effects have been extensively studied in individual topological materials, their electromagnetic coupling when integrated into heterostructures remains a vast territory for further exploration.

In this work [1], we consider a heterostructure composed of a TI slab and a single graphene layer, as depicted in Fig. 1. We further assume that a diluted concentration of ionized impurities is present in the graphene monolayer. The presence of such charged impurities will induce a local distortion of the charge density of the 2D electron gas, leading to a nontrivial electromagnetic coupling between the TI and the graphene monolayer in the heterostructure. As a probe of this coupling, we further studied the electrical conductivity as a function of temperature, by including the scattering effects with the local electromagnetic field configuration via the Kubo linear response formalism [1,2]. We applied our theoretical results to model the electromagnetic coupling in heterostructures made of different TIs (PbTe, Bi2Te3, PbSe, PbS, Bi2Se3, TlBiSe2, TbPO4). Our analytical and numerical results suggest that, among the properties of the TIs, the dielectric permittivity ε1 is the most relevant at tuning the electronic transport in the coupled graphene monolayer. On the other hand, we also observed that the topological effects arising from the presence of the MEP coefficient θ are comparatively small even at zero temperature.

References:

[1] D. Bonilla, J. Castaño-Yepes, A. Martín-Ruiz, and E. Muñoz, Physical Review B 107, 245103 (2023) https://doi.org/10.1103/PhysRevB.107.245103

[2] D. Bonilla and E. Muñoz, Nanomaterials 12, 3711 (2022) https://doi.org/10.3390/ nano12203711

[3] J. Castaño-Yepes and E. Muñoz, Annalen der Physik 202300398 (2024) https://doi.org/10.1002/andp.202300398

[4] J. Castaño-Yepes and E. Muñoz, Results in Physics 39, 105712 (2022) https://doi.org/10.1016/j.rinp.2022.105712

Topics 

Nanomaterials
Transport Phenomena

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