Gapless spin liquid behavior in two-dimensional solid 3He -: art. no. 025301

Direct demagnetization has been made for two-dimensional solid He-3 in both the paramagnetic and the antiferromagnetic phases. The lowest temperature is about 10 muK, judging from the observed magnetization for the paramagnetic solid He-3. The magnetization of the antiferromagnetic solid He-3 shows a gradual increase to about 10 muK for the 4/7 phase adsorbed on both one layer of He-4 and two layers of HD preplated graphite. This strongly suggests that the triangular antiferromagnet with the higher order multiple exchange has a quantum spin liquid ground state with nearly zero or extremely small spin gap less than 10 muK.