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Title: Composite Fermi liquid at half filling without magnetic field
Plain: At half filling of the lowest twisted-MoTe2 band, theory predicts a metal of composite fermions (electrons bound to vortices) like the one in a half-filled Landau level, but with no applied field.
Precise: In twisted bilayer MoTe2 at $\theta \sim 3.5-3.9\,\mathrm{deg}$ near hole filling $\nu = 1/2$ and $3/4$ of the first Chern band, determine whether the compressible state is an anomalous composite Fermi liquid with Fermi wavevector $k_F = \sqrt{4 \pi n_{cf}}$, $n_{cf}$ the composite-fermion density, or an ordinary Fermi liquid with Berry curvature. An answer is a direct measurement of the composite-fermion Fermi surface.
Settled by: Commensurability oscillations in an imposed periodic potential, or surface-acoustic-wave resonances, showing $k_{F}$ fixed by the composite-fermion density.
Kind: well-posed
Answer type: yes-no
References: (empty)
Literature status: partially-resolved
Status note: 2023-2024 transport found anomalous Hall resistance near $2h/e^{2}$ at $\nu = 1/2$, consistent with a composite Fermi liquid; no direct Fermi-surface measurement as of 2026.
Posed since: 2023