Magnetoresistivity in the Antiferromagnetic Hubbard Model

Abstract

We investigate the magnetotransport properties of the half-filled antiferromagnetic (AF) one-band Hubbard model under an external magnetic field using the single-site dynamical mean-field approximation (DMFT). Particular attention is paid to the mechanisms driving the magnetoresistivity behavior. We analyze the dependence of magnetoresistivity on temperature and the strength of the applied magnetic field, providing insights into the interplay between magnetic fluctuations and transport properties in AF systems.

Figures (7)

• Figure 1: Temperature dependence of the magnetization $m_A$ and $m_B$ for sublattices $A$ and $B$ under different magnetic field values $h$. The curves highlight the suppression of AF order with increasing temperature and the asymmetric alignment of spins due to the external magnetic field.
• Figure 2: Temperature dependence of magnetotransport properties for various magnetic field strengths $h$: (a) Conductivity $\sigma(T)$, (b) Resistivity $\rho(T)$ (logarithmic scale), (c) Scattering rates $\tau^{-1}_A$ and $\tau^{-1}_B$, and (d) Magnetoresistance (MR). The plots highlight the effect of the magnetic field on the system's transport properties across the temperature range studied.
• Figure 3: Normalized resistivity $\rho(h)/\rho(0) = MR + 1$ obtained for the full AF solution (solid line) and the enforced PM state (dashed line) for $h=0.08$, plotted alongside the magnetization $m_A$ and $m_B$, with and without applied field, and the scattering rates $\tau^{-1}_A$ and $\tau^{-1}_B$. All quantities are plotted in arbitrary units (a. u.) for clarity.
• Figure 4: Spectral function $A(\omega)$ as a function of real frequency $\omega$ for $h=0.08$, at various temperatures. The red and blue curves represent the spectral weight evolution for the parallel (A) and antiparallel (B) sublattices, respectively. As temperature increases, the gap for the B sublattice (blue) fills up faster than for the A sublattice (red), reflecting the asymmetry induced by the external magnetic field.
• Figure 5: Magnetization $m_A$ (upper set of curves) and $m_B$ (lower set) as a function of magnetic field strength $h$ for various fixed temperatures.