- Huiyuan Man, Johns Hopkins University, Baltimore, Maryland
A possible realization of quantum spin ice, Pr2Zr2O7, was recently shown to feature a low-temperature regime of thermal transport consistent with artificial photons in a U(1) Coulomb spin liquid. In this seminar, the speaker will provide spectroscopic evidence for the corresponding low-energy excitations through ultrahigh-resolution magnetic neutron scattering. The momentum-averaged spectrum can be described as relaxational with a rate Γ´ = 10.(4) µeV. At energies that are an order of magnitude higher, Γ = 0.15(2) meV, a separate component of scattering that may be associated with a magnetic monopole continuum is documented. Comparison of the B//(111) magnetization curve of our samples to exact diagonalization data is used to establish the underlying spin hamiltonian and the presence of two percolating networks of Pr sites with and without effective nonmagnetic dilution through ligand disorder. From the latter we find an elastic component of magnetic neutron scattering with a physical width below δE = 3.(6) µeV and a strength that is consistent with the hyperfine enhanced nuclear specific heat and a moment of 1.4 µB on 60% of the Pr sites that is static.
This will be a video presentation.