Soft Spin Wave Near nu=1: Evidence for a Magnetic Instability in Skyrmion Systems

Abstract

The ground state of the two dimensional electron gas near $ν$=1 is investigated by inelastic light scattering measurements carried down to very low temperatures. Away from $ν$=1, the ferromagnetic spin wave collapses and a new low-energy spin wave emerges below the Zeeman gap. The emergent spin wave shows soft behavior as its energy increases with temperature and reaches the Zeeman energy for temperatures above 2 K. The observed softening indicates an instability of the two dimensional electron gas towards a magnetic order that breaks spin rotational symmetry. We discuss our findings in light of the possible existence of a Skyrme crystal.

4 pages, 4 figures, to appear in Phys. Rev. Lett