Self-consistent renormalization theory of spin fluctuations in paramagnetic spinel LiV2O4

Abstract

A phenomenological description for the dynamical spin susceptibility $\chi (\mathbf{q},\omega ;T)$ observed in inelastic neutron scattering measurements on powder samples of LiV${}_2$O${}_4$ is developed in terms of the parametrized self-consistent renormalization (SCR) theory of spin fluctuations. Compatible with previous studies at $T\to 0$, a peculiar distribution in $\mathbf{q}$-space of strongly enhanced and slow spin fluctuations at $q\sim Q_c\simeq$ 0.6 ${\mathring{A}}^{-1}$ in LiV${}_2$O${}_4$ is involved to derive the mode-mode coupling term entering the basic equation of the SCR theory. The equation is solved self-consistently with the parameter values found from a fit of theoretical results to experimental data. For low temperatures, $T\lesssim 30$K, where the SCR theory is more reliable, the observed temperature variations of the static spin susceptibility $\chi (Q_c;T)$ and the relaxation rate ${\Gamma }_Q(T)$ at $q\sim Q_c$ are well reproduced by those suggested by the theory. For $T\gtrsim 30$K, the present SCR is capable in predicting only main trends in $T$-dependences of $\chi (Q_c;T)$ and ${\Gamma }_Q(T)$. The discussion is focused on a marked evolution (from $q\sim Q_c$ at $T\to 0$ towards low $q$ values at higher temperatures) of the dominant low-$\omega$ integrated neutron scattering intensity $I(q;T)$.

7 pages, 1 figure. accepted to PRB

References in corpus (2)

• Doped Mott insulator as the origin of heavy Fermion behavior in LiV2O4
• Dynamic spin susceptibility of paramagnetic spinel LiV2O4

Cited by in corpus (2)

• Effective Hamiltonian of Three-orbital Hubbard Model on Pyrochlore Lattice: Application to LiV_2O_4
• Spin fluctuations probed by NMR in paramagnetic spinel LiV${}_2$O${}_4$: a self-consistent renormalization theory