Cascade of magnetic-field-induced quantum phase transitions in a spin $1/2$ triangular-lattice antiferromagnet

N. A. Fortune, S. T. Hannahs, Y. Yoshida +4

We report magnetocaloric and magnetic-torque evidence that in Cs${}_2$CuBr${}_4$ -- a geometrically frustrated Heisenberg $S=1/2$ triangular-lattice antiferromagnet -- quantum fluc…