Unpolarized quasielectrons and the spin polarization at filling fractions between 1/3 and 2/5

TL;DR

This paper proves the relationship between ground state spin polarization and filling fractions in fractional quantum Hall systems with hard core and Coulomb interactions, and discusses experimental signatures of unpolarized quasielectrons.

Contribution

It establishes a theoretical formula for spin polarization in the specified filling range and analyzes experimental implications for unpolarized quasielectrons.

Findings

Spin polarization P=2/ν-5 for 1/3 ≤ ν ≤ 2/5.

Unpolarized quasielectrons cause peaks in tunneling I-V characteristics below 20T.

The result holds for both hard core and Coulomb interactions with small magnetic fields.

Abstract

We prove that for a hard core interaction the ground state spin polarization in the low Zeeman energy limit is given by $P=2/\nu-5$ for filling fractions in the range $ 1/3 \leq\nu\leq 2/5 $. The same result holds for a Coulomb potential except for marginally small magnetic fields. At the magnetic fields $B<20T$ unpolarized quasielectrons can manifest themselves by a characteristic peak in the I-V characteristics for tunneling between two $\nu=1/3$ ferromagnets.