Interlayer Interactions and the Fermi Energy of Bilayer Composite Fermion Metals

Abstract

When two 2D electron gas layers, each at Landau level filling factor $\nu =1/2$, are close together a condensate of interlayer excitons emerges at low temperature. Although the excitonic phase is qualitatively well understood, the incoherent phase just above the critical layer separation is not. Using a combination of interlayer tunneling spectroscopy and conventional transport, we explore the incoherent phase in samples both near the phase boundary and further from it. In the more closely spaced bilayers we find the electronic spectral functions narrower and the Fermi energy of the $\nu =1/2$ composite fermion metal smaller than in the more widely separated bilayers. We attribute these effects to a softening of the intralayer Coulomb interaction due to interlayer screening.

5 pages, 3 postscript figures. Final published version

References in corpus (4)

• Spin Transition in the Half-Filled Landau Level
• Tunnel transport and interlayer excitons in bilayer fractional quantum Hall systems
• Effect of magnetization on the tunneling anomaly in compressible quantum Hall states
• Semiclassical theory of the tunneling anomaly in partially spin-polarized compressible quantum Hall states

Cited by in corpus (3)

• Variational Ansatz for an Abelian to non-Abelian Topological Phase Transition in $\nu =1/2+1/2$ Bilayers
• Precursors to Exciton Condensation in Quantum Hall Bilayers
• Tunneling density of states, correlation energy, and spin polarization in the fractional quantum Hall regime