Journal of Physics: Conference Series
In classical magnetic spin systems, geometric frustration leads to a large number of states of identical energy. We report here evidence from magnetocaloric and related measurements that in Cs2CuBr4 — a geometrically frustrated Heisenberg S= 1/2 triangular antiferromagnet — quantum fluctuations stabilize a series of gapped collinear spin states bounded by first-order transitions at simple increasing fractions of the saturation magnetization for fields directed along the c axis. Only the first of these quantum phase transitions has been theoretically predicted, suggesting that quantum effects continue to dominate at fields much higher than previously considered.
⃝c 2010 IOP Publishing Ltd
Fortune, Nathanael Alexander; Hannahs, Scott T.; Takano, Y.; Yoshida, Y.; Sherline, T.; Wilson-Muenchow, A. A.; Ono, T.; and Tanaka, H., "Field-induced Quantum Phase Transitions in the Spin-1/2 Triangular-lattice Antiferromagnet Cs2CuBr4" (2010). Physics: Faculty Publications, Smith College, Northampton, MA.