Spin-dependent heat and thermoelectric currents in a Rashba ring coupled to a photon cavity

Abdullah, Nzar Rauf; Tang, Chi-Shung; Manolescu, Andrei; Guðmundsson, Viðar

doi:10.1016/j.physe.2017.09.011

Cited by 14 publications

(19 citation statements)

References 31 publications

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“…The 2D graphene structure consisting of carbon atoms arranged in a honeycomb structure with an sp 2 hybridization has been of interest for future nanotechnology [1], and it is the most promising material for implementing the next generation of electronic devices [2]. Fascinating properties of graphene such as ballistic transport at room temperature, high mobility, high electronic conductivity, quantum Hall effect, electrically controllable spin transportand [3,4], and mechanical strength make graphene a potential candidate for an enormous breadth of applications [5,6] in electronic [7], optical [8,9,10,11], and thermoelectric [12,13] devices.…”

Section: Introductionmentioning

confidence: 99%

Effects of bonded and non-bonded B/N codoping of graphene on its stability, interaction energy, electronic structure, and power factor

et al. 2020

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We model boron and nitrogen doped/codoped monolayer graphene to study its stability, interaction energy, electronic and thermal properties using density functional theory. It is found that a doped graphene sheet with non-bonded B or N atoms induces an attractive interaction and thus opens up the bandgap. Consequently, the power factor is enhanced. Additionally, bonded B or N atoms in doped graphene generate a repulsive interaction leading to a diminished bandgap, and thus a decreased power factor. We emphasis that enhancement of the power factor is not very sensitive to the concentration of the boron and nitrogen atoms, but it is more sensitive to the positions of the B or N atoms in ortho, meta, and para positions of the hexagonal structure of graphene. In the B and N codoped graphene, the non-bonded dopant atoms have a weak attractive interaction and interaction leading to a small bandgap, while bonded doping atoms cause a strong attractive interaction and a large bandgap. As a result, the power factor of the graphene with non-bonded doping atoms is reduced while it is enhanced for graphene with bonded doping atoms.

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Section: Introductionmentioning

confidence: 99%

Effects of bonded and non-bonded B/N codoping of graphene on its stability, interaction energy, electronic structure, and power factor

et al. 2020

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“…2, we present the energy spectrum of the QR system without (a), and with (b) the photon field. The data reveals a crossing of one-electron states around α = [11][12][13][14][15][16] meV nm (green rectangle region) corresponding to the Aharonov-Casher (AC) destructive phase interference 18 . The crossing of one-electron states forms the so called degenerate energy states.…”

Section: Resultsmentioning

confidence: 99%

“…Figure 3 indicates the spin polarization versus the Rashba coefficient for the system without (w/o) and with (w) the photon field. We can see that the spin polarization in the x-and z-directions, S x and S z , vanishes while the spin polarization S y in the y-direction has nonzero value for the Rashba coupling constant around α = [11][12][13][14][15][16] meV nm corresponding to the degeneracy of the energy states shown in Fig. 2.…”

Section: A Spin Polarizationmentioning

confidence: 99%

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Photon-induced tunability of the thermospin current in a Rashba ring

Abdullah

Arnold

Tang

et al. 2018

J. Phys.: Condens. Matter

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The goal of this work is to show how the thermospin polarization current in a quantum ring changes in the presence of Rashba spin-orbit coupling and a quantized single photon mode of a cavity the ring is placed in. Employing the reduced density operator and a general master equation formalism, we find that both the Rashba interaction and the photon field can significantly modulate the spin polarization and the thermospin polarization current. Tuning the Rashba coupling constant, degenerate energy levels are formed corresponding to the Aharonov-Casher destructive phase interference in the quantum ring system. Our analysis indicates that the maximum spin polarization can be observed at the points of degenerate energy levels due to spin accumulation in the system without the photon field. The thermospin current is thus suppressed. In the presence of the cavity, the photon field leads to an additional kinetic momentum of the electron. As a result the spin polarization can be enhanced by the photon field.

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“…The ring system is embedded in a cavity with a linearly polarized photon field. In our previous publications, we have seen that both thermoelectric and heat currents can be controlled by a polarized photon field [13,14,15,16]. The aim of our study here is twofold.…”

Section: Introductionmentioning

confidence: 97%

Single-photon controlled thermospin transport in a resonant ring-cavity system

Abdullah

Guðmundsson

2018

Physica E: Low-dimensional Systems and Nanostructures

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Cavity-coupled nanoelectric devices hold great promise for quantum technology based on coupling between electronspins and photons. In this study, we approach the description of these effects through the modeling of a nanodevice using a quantum master equation. We assume a quantum ring is coupled to two external leads with different temperatures and embedded in a cavity with a single photon mode. Thermospin transport of the ring-cavity system is investigated by tuning the Rashba coupling constant and the electron-photon coupling strength. In the absence of the cavity, the temperature gradient of the leads causes a generation of a thermospin transport in the ring system. It is observed that the induced spin polarization has a maximum value at the critical value of the Rashba coupling constant corresponding to the Aharonov-Casher destructive interference, where the thermospin current is efficiently suppressed. Embedded in a photon cavity with the photon energy close to a resonance with the energy spacing between lowest states of the quantum ring, a Rabi splitting in the energy spectrum is observed. Furthermore, photon replica states are formed leading to a reduction in the thermospin current.

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Spin-dependent heat and thermoelectric currents in a Rashba ring coupled to a photon cavity

Cited by 14 publications

References 31 publications

Effects of bonded and non-bonded B/N codoping of graphene on its stability, interaction energy, electronic structure, and power factor

Effects of bonded and non-bonded B/N codoping of graphene on its stability, interaction energy, electronic structure, and power factor

Photon-induced tunability of the thermospin current in a Rashba ring

Single-photon controlled thermospin transport in a resonant ring-cavity system

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