Effect of magnetization on the tunneling anomaly in compressible quantum Hall states

TL;DR

This paper develops a new theoretical framework for understanding the tunneling anomaly in spin-polarized quantum Hall states, emphasizing the role of composite fermion compressibility, to better match recent experimental observations.

Contribution

It introduces a novel regime where the charge-spreading action depends on composite fermion compressibility, challenging the conventional Coulomb self-energy approach.

Findings

Conventional Coulomb-based models are inconsistent with experiments.

Proposes a regime where composite fermion compressibility dominates.

Aligns theoretical predictions with experimental suppression of tunneling.

Abstract

Tunneling of electrons into a two-dimensional electron system is known to exhibit an anomaly at low bias, in which the tunneling conductance vanishes due to a many-body interaction effect. Recent experiments have measured this anomaly between two copies of the half-filled Landau level as a function of in-plane magnetic field, and they suggest that increasing spin polarization drives a deeper suppression of tunneling. Here we present a theory of the tunneling anomaly between two copies of the partially spin-polarized Halperin-Lee-Read state, and we show that the conventional description of the tunneling anomaly, based on the Coulomb self-energy of the injected charge packet, is inconsistent with the experimental observation. We propose that the experiment is operating in a different regime, not previously considered, in which the charge-spreading action is determined by the compressibility of the composite fermions.