TY - JOUR
T1 - Non-Fermi liquid behaviour below the Néel temperature in the frustrated heavy Fermion magnet UAu2
AU - O'Neill, Christopher D.
AU - Schmehr, Julian L
AU - Keen, Harry D. J.
AU - Pritchard Cairns, Luke
AU - Sokolov, Dmitry A
AU - Hermann, Andreas
AU - Wermeille, Didier
AU - Manuel, Pascal
AU - Kruger, Frank
AU - Huxley, Andrew D.
PY - 2021/12/7
Y1 - 2021/12/7
N2 - The term Fermi liquid is almost synonymous with the metallic state. The association is known to break down at quantum critical points (QCPs), but these require precise values of tuning parameters, such as pressure and applied magnetic field, to exactly suppress a continuous phase transition temperature to the absolute zero. Three-dimensional non-Fermi liquid states, apart from superconductivity, that are unshackled from a QCP are much rarer and are not currently well understood. Here, we report that the triangular lattice system uranium diauride (UAu2) forms such a state with a non-Fermi liquid low-temperature heat capacity C/T∼log (1/T) and electrical resistivity ρ(T)−ρ(0)∝T1.35 far below its Néel temperature. The magnetic order itself has a novel structure and is accompanied by weak charge modulation that is not simply due to magnetostriction. The charge modulation continues to grow in amplitude with decreasing temperature, suggesting that charge degrees of freedom play an important role in the non-Fermi liquid behavior. In contrast with QCPs, the heat capacity and resistivity we find are unusually resilient in magnetic field. Our results suggest that a combination of magnetic frustration and Kondo physics may result in the emergence of this novel state.
AB - The term Fermi liquid is almost synonymous with the metallic state. The association is known to break down at quantum critical points (QCPs), but these require precise values of tuning parameters, such as pressure and applied magnetic field, to exactly suppress a continuous phase transition temperature to the absolute zero. Three-dimensional non-Fermi liquid states, apart from superconductivity, that are unshackled from a QCP are much rarer and are not currently well understood. Here, we report that the triangular lattice system uranium diauride (UAu2) forms such a state with a non-Fermi liquid low-temperature heat capacity C/T∼log (1/T) and electrical resistivity ρ(T)−ρ(0)∝T1.35 far below its Néel temperature. The magnetic order itself has a novel structure and is accompanied by weak charge modulation that is not simply due to magnetostriction. The charge modulation continues to grow in amplitude with decreasing temperature, suggesting that charge degrees of freedom play an important role in the non-Fermi liquid behavior. In contrast with QCPs, the heat capacity and resistivity we find are unusually resilient in magnetic field. Our results suggest that a combination of magnetic frustration and Kondo physics may result in the emergence of this novel state.
U2 - 10.1073/pnas.2102687118
DO - 10.1073/pnas.2102687118
M3 - Article
VL - 118
JO - Proceedings of the National Academy of Sciences (PNAS)
JF - Proceedings of the National Academy of Sciences (PNAS)
SN - 0027-8424
IS - 49
M1 - e2102687118
ER -