Publications by authors named "Mark D Lumsden"
The Kitaev quantum spin liquid (KQSL) is an exotic emergent state of matter exhibiting Majorana fermion and gauge flux excitations. The magnetic insulator α-RuCl is thought to realize a proximate KQSL. We used neutron scattering on single crystals of α-RuCl to reconstruct dynamical correlations in energy-momentum space.
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- The study focuses on understanding electronic correlations in complex materials, particularly the balance between localized and itinerant electronic behaviors.
- Researchers used neutron spectroscopy to examine plutonium, a material at the boundary between different electronic configurations.
- Findings indicate that plutonium's ground state is influenced by valence fluctuations, supporting predictions from theory and helping to clarify its magnetic properties as well as the broader implications for other complex materials.
Inelastic neutron scattering measurements of individual phonon lifetimes and dispersion at 295 and 1200 K have been used to probe anharmonicity and thermal conductivity in UO2. They show that longitudinal optic phonon modes carry the largest amount of heat, in contrast to past simulations and that the total conductivity demonstrates a quantitative correspondence between microscopic and macroscopic phonon physics. We have further performed first-principles simulations for UO2 showing semiquantitative agreement with phonon lifetimes at 295 K, but larger anharmonicity than measured at 1200 K.
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