Knight Shift and Nuclear Spin Relaxation Rate in a Charge-Ordered State of the One-Dimensional Extended Hubbard Model at Quarter Filling

Abstract

We investigate Knight shift and nuclear spin relaxation rate in a charge ordered state of the one-dimensional extended Hubbard model with a quarter filled band by using RPA around the mean-field solution. It is shown that both quantities show splitting below the critical temperature of the charge order, as is experimentally observed. The relationship between the mount of the splitting in the both quantities and the charge disproportionation rate is discussed.

Charge-Ordered State versus Dimer-Mott Insulator at Finite Temperatures

“…Then the 4k F -component of the density operators is expressed in part by the q = 0 density operators around the Fermi energy, namely, the slowly-varying component of the charge/spin density becomes a part of its 4k F component. This is directly related to the splitting in the NMR spectrum since the response under uniform magnetic field at each site becomes disproportionated with a period of two sites 27 reflecting the Knight shift. In the phase representation, the staggered component of the spin density m 4kF (x) is proportional to the slowly varying component of the spin density…”

Knight shift in the charge ordered states of the one-dimensional electron systems at 14 filling

“…The observation that the shift of resonance frequency of NMR shows splitting and/or the relaxation rate of the nuclear spin becomes multi-components has been considered to be the experimental evidence of CO [2][3][4]. In fact, in the case of CO with a 2-fold periodicity of the onedimensional (1D) systems, the above have been proved theoretically [5]. However, it is not obvious whether the splitting reflects the charge disproportionation or enlargement of the periodicity in the charge ordered state.…”

Finite-Temperature Phase Transitions in Quasi-One-Dimensional Molecular Conductors

“…12 Several have actually studied finite-T properties of these models. Mean-field studies have been performed, [13][14][15] but such an approach fails, in general, to reproduce paramagnetic insulating phases which are observed in the above compounds at intermediate T . Moreover, when fluctuation effects are properly taken into account, purely electronic 1D models do not show phase transitions unless T = 0.…”