| Measurements of composite Skyrmions at filling factor 1/3 (2008) | |||||||||||||
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| Measurements of the fractional quantum Hall effect energy gaps at high pressures are presented that provide evidence for the existence of composite Skyrmions. Just as charged spin textures known as Skyrmions are thought to be the lowest lying excitations for electrons at ν=1, we show that composite Skyrmions can be formed at ν=1/3 when the electron g-factor is sufficiently small. Keywords: Fractional quantum Hall effect, Skyrmions, composite Fermions. The fully polarised fractional quantum Hall effect (FQHE) state at filling factor ν=1/3 consists of exactly one full composite Fermion Landau level (CF LL) and as such is completely analogous to the integer quantum Hall state at ν=1. Indeed the fact that Laughlin’s wavefunction for ν=1/3 contains the ν=1 wavefunction as a factor is one of the basis for the composite Fermion model [1]. Thus, as at all odd ν, the ground state at ν=1/3 should be seen as an itinerant ferromagnet. Excitations from these ferromagnetic ground states, which determine the conductivity, are dominated by the Coulomb exchange energy, Ec=e 2 /4πε lB (lB = h eB is the magnetic length) which is much larger than the single particle Zeeman energy gμBB. Single spin flips generate spin waves [2], but, if the Zeeman energy is not too large, there may be spin-textured chiral solitons | |||||||||||||
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