Quantum phase transitions for the three-dimensional orthogonal-dimer spin system Original Research Article

We discuss the phase diagram of the three-dimensional orthogonal-dimer system for the compound SrCu2(BO3)2. By performing the computer-aided series expansion, we investigate quantum phase transitions among the dimer phase, the frustration-induced disordered phase and the magnetically ordered phase. It is claimed that the compound SrCu2(BO3)2 is located in the dimer phase close to a tri-critical phase transition point.