Enhancement of superconductivity mediated by antiferromagnetic squeezed magnons

Erlandsen, Eirik; Kamra, Akashdeep; Brataas, Arne; Sudbø, Asle

doi:10.1103/physrevb.100.100503

Cited by 50 publications

(88 citation statements)

References 79 publications

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“…We then still have the required signs in order to obtain a nontrivial solution to the gap equation, and obtain a boosting from the A-factor, for Ω < 1, in exactly the same way as was obtained in NM/AFMI case of Ref. [16]. For Ω = 0, the interaction potential is therefore much stronger than the potential we had in the FMI case.…”

Section: Pairingmentioning

confidence: 71%

“…The main result of the paper, which is expected to be ro-bust, is that the strength of the fermion-fermion interaction mediated by antiferromagnetic magnons, analogously to the NM/AFMI case of Ref. [16], is enhanced by coupling asymmetrically to the two sublattices of the AFMI. The interaction strength is therefore significantly larger than for an FMI.…”

Section: Introductionmentioning

confidence: 91%

“…This enhancement can be understood from the picture of antiferromagnetic magnons as squeezed states, revealing that an antiferromagnetic magnon is associated with a large spin located at each sublattice [22]. Coupling to only one of the two sublattices of an AFMI thereby involves coupling to a large spin, leading to a strong enhancement of the coupling interaction [16,23].…”

Section: Introductionmentioning

confidence: 99%

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Magnon-mediated superconductivity on the surface of a topological insulator

2020

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We study superconductivity on the surface of a topological insulator, mediated by magnetic fluctuations in an adjacent ferromagnetic or antiferromagnetic insulator. Superconductivity can arise from effective interactions between helical fermions induced by interfacial fermion-magnon interactions. For both ferromagnetic and antiferromagnetic insulators, these fermion-fermion interactions have the correct structure to facilitate pairing between particles located on the same side of the Fermi surface, also known as Amperean pairing. In antiferromagnets, the strength of the induced interactions can be enhanced by coupling the topological insulator asymmetrically to the two sublattices of the antiferromagnet. This effect is further amplified by next nearest neighbor frustration in the antiferromagnetic insulator. The enhancement makes the induced interactions significantly stronger in the antiferromagnetic case, as compared to the ferromagnetic case. These results indicate that an uncompensated antiferromagnetic interface might be a better candidate than a ferromagnetic interface for proximity-induced magnon-mediated superconductivity on the surface of a topological insulator. arXiv:1912.07607v2 [cond-mat.supr-con]

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Section: Pairingmentioning

confidence: 71%

Section: Introductionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

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Magnon-mediated superconductivity on the surface of a topological insulator

2020

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“…These excitations are quasiparticles known as magnons. Theoretical predictions of electron-magnon interactions have shown that these can also induce effects such as superconductivity [1][2][3][4][5][6][7][8][9][10].Research interest in antiferromagnetic materials is surging [11,12]. This enthusiasm is due to the promising properties of antiferromagnets such as high resonance frequencies in the THz regime and a vanishing net magnetic moment.…”

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confidence: 99%

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confidence: 99%

Magnon-Mediated Indirect Exciton Condensation through Antiferromagnetic Insulators

et al. 2019

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Electrons and holes residing on the opposing sides of an insulating barrier and experiencing an attractive Coulomb interaction can spontaneously form a coherent state known as an indirect exciton condensate. We study a trilayer system where the barrier is an antiferromagnetic insulator. The electrons and holes here additionally interact via interfacial coupling to the antiferromagnetic magnons. We show that by employing magnetically uncompensated interfaces, we can design the magnon-mediated interaction to be attractive or repulsive by varying the thickness of the antiferromagnetic insulator by a single atomic layer. We derive an analytical expression for the critical temperature T c of the indirect exciton condensation. Within our model, anisotropy is found to be crucial for achieving a finite T c , which increases with the strength of the exchange interaction in the antiferromagnetic bulk. For realistic material parameters, we estimate T c to be around 7 K, the same order of magnitude as the current experimentally achievable exciton condensation where the attraction is solely due to the Coulomb interaction. The magnon-mediated interaction is expected to cooperate with the Coulomb interaction for condensation of indirect excitons, thereby providing a means to significantly increase the exciton condensation temperature range.Introduction.-Interactions between fermions result in exotic states of matter. Superconductivity is a prime example, where the negatively charged electrons can have an overall attractive coupling mediated by individual couplings to the vibrations, known as phonons, of the positively charged lattice. In addition to charge, the electron also has a spin degree of freedom. The electron spin can interact with localized magnetic moments through an exchange interaction exciting the magnetic moment by transfer of angular momentum. These excitations are quasiparticles known as magnons. Theoretical predictions of electron-magnon interactions have shown that these can also induce effects such as superconductivity [1][2][3][4][5][6][7][8][9][10].Research interest in antiferromagnetic materials is surging [11,12]. This enthusiasm is due to the promising properties of antiferromagnets such as high resonance frequencies in the THz regime and a vanishing net magnetic moment. Much of this research focuses on interactions involving magnons or spin waves at magnetic interfaces in hybrid structures. Examples of this are spin pumping [13-19], spin transfer [15, 20-22], and spin Hall magnetoresistance [23-28] at normal metal interfaces, and magnon-mediated superconductivity [9,10]. Recently, an experiment has also demonstrated spin transport in an antiferromagnetic insulator over distances up to 80 µm [29]. Moreover, antiferromagnetic materials are also of interest since it is believed that high-temperature superconductivity in cuprates is intricately linked to magnetic fluctuations near an antiferromagnetic Mott insulating phase [30,31]. Thus it is crucial to achieve a good understanding of antiferromagnetic magn...

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Spin Resistivity in a Metallic Channel Induced by Antiferromagnetic Approximation Effect

Pimentel

2024

Braz J Phys

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Enhancement of superconductivity mediated by antiferromagnetic squeezed magnons

Cited by 50 publications

References 79 publications

Magnon-mediated superconductivity on the surface of a topological insulator

Magnon-mediated superconductivity on the surface of a topological insulator

Magnon-Mediated Indirect Exciton Condensation through Antiferromagnetic Insulators

Spin Resistivity in a Metallic Channel Induced by Antiferromagnetic Approximation Effect

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