Optical response of a topological-insulator–quantum-dot hybrid interacting with a probe electric field

Abstract

We study the interaction between a topological insulator nanoparticle and a quantum dot subject to an applied electric field. The electromagnetic response of the topological insulator is derived from axion electrodynamics in the quasistatic approximation. Localized modes are quantized in terms of dipolar bosonic modes, which couples dipolarly to the quantum dot. Hence, we treat the hybrid as a two-level system interacting with a single bosonic mode, where the coupling strength encodes the information concerning the nontrivial topology of the nanoparticle. The interaction of the hybrid with the environment is implemented through the coupling with a continuum reservoir of radiative output modes and a reservoir of phonon modes. In particular, we use the method of Zubarev's Green functions to derive an expression for the optical absorption spectrum of the system. We apply our results to a realistic system which consists of a topological insulator nanoparticle made of TlBiSe2 interacting with a cadmium selenide quantum dot, both immersed in a polymer layer such as poly(methyl methacrylate). The optical absorption spectrum exhibits Fano resonances with a line shape that strongly depends on the polarization of the electric field as well as on the topological magnetoelectric polarizability θ. Our results and methods can also be applied to nontopological magnetoelectric materials such as Cr2O3.

Ground state and polarization of an hydrogen-like atom near a Weyl semimetal

“…Some works have been done in this spirit. For example, some particular classical electrodynamics configurations both in TIs [34][35][36][37][38][39] and WSMs [40][41][42][43][44], the frequency shift induced by the Casimir-Polder interaction between atoms and TIs [45][46][47], and the optical absorption of semiconductor-TI quantum dots [48][49][50], among others. Moved by these researches, in this paper we investigate the effects of a Weyl semimetallic phase upon hydrogenlike ions near its surface, taking into account the modifications arising from the topological nontriviality of the material.…”

Tailoring topological states of core–shell nanoparticles

“…In recent years, nanoparticles based on TIs have been thoroughly investigated for their interest in photonics, optically controlled quantum memory and quantum computing [8][9][10][11][12][13][14]. Surface states * Corresponding author show little sensitivity to disorder, which is beneficial for optical applications at the nanoscale [10].…”

Reversed Phase Transformation of β→α-Sn at Elevated Temperatures towards Quantum Material Integration on Silicon

“…The TDS Sn microdots could potentially be coupled through graphene or quantum dots towards quantum device applications. [36][37][38] . They also demonstrated optical absorption at ∼1250-1750 nm wavelength, which may enable quantum state switching by optical excitation 39 at 1310-1550 nm telecommunication wavelengths, potentially through integration with silicon photonics.…”