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.
©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.