Experimental signatures of a three-dimensional quantum spin liquid in effective spin-1/2 Ce<sub>2</sub>Zr<sub>2</sub>O<sub>7</sub> pyrochlore
· Invited
Abstract
A quantum spin liquid (QSL) is an exotic state of matter where unpaired electrons’ spins, although being entangled, do not show magnetic order even at the zero-temperature. Because such a state may be important to the microscopic origin of high-transition temperature superconductivity and useful for quantum computation, the experimental realization of QSL is a long-sought goal in condensed matter physics. Previous neutron scattering experiments on the two-dimensional QSL candidates ZnCu3(OD)6Cl2 and YbMgGaO4 have found evidence for the hallmark of a QSL at very low temperature - a continuum of magnetic excitations. However, the presence of site disorder complicates the interpretation of the data. Recently, the three-dimensional (3D) Ce3+ pyrochlore lattice Ce2Sn2O7 has been suggested as a clean, effective spin-1/2 QSL candidate, but the evidence of a spin excitation continuum is missing due to the lack of single crystals. Until 2019, the first single-crystal study of Ce2Zr2O7, a compound isostructural to Ce2Sn2O7, reveals the absence of magnetic ordering/spin-glass down to 20 mK and the presence of a spin excitation continuum at 35 mK. With no evidence of oxygen deficiency and chemical disorder seen by diffuse scattering measurements and neutron diffraction, Ce2Zr2O7 may be a 3D pyrochlore lattice QSL material with minimum magnetic and nonmagnetic chemical disorder. Recent works including elastic and inelastic neutron scattering measurements under magnetic fields, as well as diffusive scattering in Ce2Zr2O7 in large Q ranges, may help identify the system as an octupolar U(1) QSL.
*US DOE BES DE-SC0012311, DE-FG02-04ER46105, DE-SC0019503
Robert A. Welch. Foundation under grant no. C-1839
cQMS (EPiQS - GBMF6402)
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Presenters
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Bin Gao
- Rice University
- Rutgers Center for Emergent Materials, Rutgers University
- Department of Physics and astronomy, Rice University
- Department of Physics and Astronomy, Rice University
- Rice Univ