Experimental Evidence for Rare Quantum Disordered Phase in Cerium-Based Magnet Ce2Zr2O7

New experimental evidence for a rare quantum spin liquid phase in Ce₂Zr₂O₇ has been provided by analysis of neutron scattering, heat capacity, and magnetic susceptibility measurements. A quantum spin liquid is an enigmatic and extremely sought-after magnetic phase in which the magnetic spins remain disordered and fluctuate in a quantum-entangled manner down to zero temperature. They are of great interest, as they possess novel excited states for whom we have little familiarity. Furthermore, the long-ranged quantum-entanglement in these systems is a requirement for quantum technologies including quantum computing. Ce₂Zr₂O₇ is a particular quantum spin liquid candidate that has been gaining much attention recently, offering the possibility for new quantum spin liquid phases at low temperature due to the “dipolar-octupolar” character of the cerium magnetic spins. This new work lays out in detail the case for such a quantum spin liquid phase at low temperature in Ce₂Zr₂O₇ and identifies this as a novel quantum spin liquid phase near the boundary between “dipolar” and “octupolar” nature. This work establishes interaction parameters in Ce₂Zr₂O₇, thereby raising the level of discussion in this and related quantum spin liquid candidate materials.  It also employs a novel marriage between theory and experiment which will find broad applicability in understanding of novel phases of magnetic materials.