Superconductivity at metal-antiferromagnetic insulator interfaces

Eirik Løhaugen Fjærbu; Niklas Rohling; Arne Brataas

doi:10.1103/PhysRevB.100.125432

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Superconductivity at metal-antiferromagnetic insulator interfaces

Eirik Løhaugen Fjærbu, Niklas Rohling, Arne Brataas

DOI 10.1103/PhysRevB.100.125432 · Physical Review B

T1

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Abstract

Magnons in antiferromagnetic insulators couple strongly to conduction electrons in adjacent metals. We show that this interfacial tie can lead to superconductivity in a trilayer consisting of a metal sandwiched between two antiferromagnetic insulators. The strength of the induced electron-electron coupling, and consequently the critical temperature, strongly increases with increasing interface exchange coupling. For a fixed electron-electron coupling strength, the critical temperature is proportional to the magnon gap, a natural energy scale. However, the magnon gap also enters in the coupling strength, so that in the weak coupling limit, an enhancement of the magnon gap reduces the critical temperature. We estimate the critical temperature in MnF2-Au-MnF2 to be on the order of 1K. Umklapp scattering at metal-antiferromagnet interfaces leads to d-wave pairing, in contrast to p-wave superconductivity mediated by magnons in ferromagnets.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
MnF2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	1	Pressure not reported	unknown
Au Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	1	Pressure not reported	unknown