U(1) quantum spin liquids in dipolar-octupolar pyrochlore magnets: A fermionic parton approach

We study the uniform $\text{U}(1)$ quantum spin liquid (QSL) with low-energy fermionic quasiparticles for pyrochlore magnets with dipolar-octupolar symmetry, employing a fermionic parton mean-field theory approach. Self-consistent calculations stabilize 12 fully symmetric uniform $\text{U}(1)$ QSLs, of which four mean-field states are ``monopole-flux'' states. Several of these mean-field states show a linear temperature dependence of specific heat at low temperatures, the other phases show a power-law temperature dependence of specific heat $C\ensuremath{\sim}{T}^{\ensuremath{\alpha}}$. The linear temperature dependence of specific heat at low temperatures is reminiscent of the observations in ${\text{Nd}}_{2}{\text{ScNbO}}_{7}$. We further compute the dynamic spin structure factors and discuss the possible signature of these fermionic spinons in neutron-scattering experiments.