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Gauge Fields and Pairing in Double-Layer Composite Fermion Metals

N. E. Bonesteel·I. A. McDonald·C. Nayak
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Abstract

A symmetrically doped double layer electron system with total filling fraction $ν=1/m$ decouples into two even denominator ($ν=1/2 m$) composite fermion `metals' when the layer spacing is large. Out-of-phase fluctuations of the statistical gauge fields in this system mediate a singular attractive pairing interaction between composite fermions in different layers. A strong-coupling analysis shows that for any layer spacing $d$ this pairing interaction leads to the formation of a paired quantum Hall state with a zero-temperature gap $Δ(0) \propto 1/d^2$. The less singular in-phase gauge fluctuations suppress the size of the zero-temperature gap, $Δ(0) \propto 1/\left({d^2}{(\ln d)^6}\right)$, but do not eliminate the instability.

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N. E. Bonesteel, I. A. McDonald, C. Nayak. 1996-01-23. Gauge Fields and Pairing in Double-Layer Composite Fermion Metals. https://doi.org/10.1103/physrevlett.77.3009

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