Zero-field edge plasmons in a magnetic topological insulator

Mahoney, Alice; Colless, James; Peeters, Lucas; Pauka, Sebastian; Fox, Eli; Kou, Xufeng; Pan, Lei; Wang, Kang L.; Goldhaber‐Gordon, David; Reilly, David

doi:10.1038/s41467-017-01984-5

Cited by 50 publications

(41 citation statements)

References 36 publications

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“…The case for transverse plasmon excitations will be reported elsewhere. Note that the plasmon excitations studied here essentially differ from the edge magnetoplasmon with no magnetic fields observed in the topological nontrivial phase [25]. Plasmon in lightly doped QAH systems.-In reality, the system might be metallic due to defects, self-doping, and charge transfer from substrates, gating, etc.…”

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confidence: 79%

“…Recently, the experimental observation of the quantum anomalous Hall (QAH) effect [13,14] has been reported in magnetically doped ultrathin films of topological insulators V-or Cr-doped (Bi, Sb) 2 Te 3 [15][16][17], in which its band topology can be tuned by external fields. On the other hand, some recent experimental efforts have been made on observing the plasmon excitations in the bulk or surface of both the magnetic and nonmagnetic 3D topological insulators [18][19][20][21][22][23][24][25][26]. The frequency of these plasmon excitations ranges from terahertz to far infrared and facilitates a wide variety of applications of topological insulators, such as in information and communication, chemical and biological sensing, and medical sciences [27][28][29].…”

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confidence: 99%

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Tunable Intrinsic Plasmons due to Band Inversion in Topological Materials

2017

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The band inversion has led to rich physical effects in both topological insulators and topological semimetals. It has been found that the inverted band structure with the Mexican-hat dispersion could enhance the interband correlation leading to a strong intrinsic plasmon excitation. Its frequency ranges from several meV to tens of meV and can be effectively tuned by the external fields. The electron-hole asymmetric term splits the peak of the plasmon excitation into double peaks. The fate and properties of this plasmon excitation can also act as a probe to characterize the topological phases even in the lightly doped systems. We numerically demonstrate the impact of the band inversion on plasmon excitations in magnetically doped thin films of three-dimensional strong topological insulators, V-or Cr-doped (Bi,Sb)2Te3, which support the quantum anomalous Hall states. Our work thus sheds some new light on the potential applications of topological materials in plasmonics.Introduction.-Plasmons are ubiquitous collective density oscillations of an electron liquid and can occur in metals, doped semiconductors and semimetals [1,2]. The frequency of plasmon excitation is usually proportional to the density of states (DOS) of carriers at the Fermi level in the long wavelength limit [3]. In systems with vanishing DOS at the Fermi level, however, it had been demonstrated that strong correlation, higher order term in the effective mass, and the chiral anomaly could give rise to exotic plasmon excitations at zero temperature in the context of two dimensional (2D) Anderson insulators [4], graphene [5], HgTe quantum well [6], and threedimensional (3D) Weyl semimetals [7], respectively. In this paper, we reveal a new mechanism based on the band inversion with the Mexican-hat dispersion that can be used to excite and manipulate intrinsic plasmon excitations in topological materials even with vanishing DOS.

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confidence: 79%

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confidence: 99%

Tunable Intrinsic Plasmons due to Band Inversion in Topological Materials

2017

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“…The electrical current flowing in capacitively coupled devices is carried by low energy and long wavelength plasmonic excitations localized at the edge of the QH material; these excitations are usually called edge magnetoplasmons (EMPs). The physics of EMPs has been studied in depth in a variety of different cases [36][37][38][39][40][41][42][43][44][45][46][47]. We use here a semiclassical model that captures the main features of these excitations and we adapt it to describe actual devices, such as the ones in [15].…”

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confidence: 99%

Transmission lines and resonators based on quantum Hall plasmonics: Electromagnetic field, attenuation, and coupling to qubits

Bosco

DiVincenzo

2019

Phys. Rev. B

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Quantum Hall edge states have some characteristic features that can prove useful to measure and control solid state qubits. For example, their high voltage to current ratio and their dissipationless nature can be exploited to manufacture low-loss microwave transmission lines and resonators with a characteristic impedance of the order of the quantum of resistance h/e 2 ∼ 25kΩ. The high value of the impedance guarantees that the voltage per photon is high and for this reason high impedance resonators can be exploited to obtain larger values of coupling to systems with a small charge dipole, e.g. spin qubits. In this paper, we provide a microscopic analysis of the physics of quantum Hall effect devices capacitively coupled to external electrodes. The electrical current in these devices is carried by edge magnetoplasmonic excitations and by using a semiclassical model, valid for a wide range of quantum Hall materials, we discuss the spatial profile of the electromagnetic field in a variety of situations of interest. Also, we perform a numerical analysis to estimate the lifetime of these excitations and, from the numerics, we extrapolate a simple fitting formula which quantifies the Q factor in quantum Hall resonators. We then explore the possibility of reaching the strong photonqubit coupling regime, where the strength of the interaction is higher than the losses in the system. We compute the Coulomb coupling strength between the edge magnetoplasmons and singlet-triplet qubits, and we obtain values of the coupling parameter of the order 100MHz; comparing these values to the estimated attenuation in the resonator, we find that for realistic qubit designs the coupling can indeed be strong. * bosco@physik.rwth-aachen.de † d.divincenzo@fz-juelich.de A. Far-field analysis 1. EMPs in the half-plane

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“…Such events led us to coin the term ‘ Quantum sequencing ’. Similar improvements are already evident, and areas such as drug design are benefiting from them . At the current pace of technological evolution in the field, the technologies that may emerge in the near future are hard to predict.…”

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confidence: 89%