scholarly journals Efficient fluctuation-exchange approach to low-temperature spin fluctuations and superconductivity: From the Hubbard model to NaxCoO2·yH2O

2021 ◽  
Vol 103 (20) ◽  
Author(s):  
Niklas Witt ◽  
Erik G. C. P. van Loon ◽  
Takuya Nomoto ◽  
Ryotaro Arita ◽  
Tim O. Wehling
Keyword(s):  
Low Temperature ◽  
Hubbard Model ◽  
Spin Fluctuations

Application of the Landau-Luttinger Liquid Formulation to the Study of the Magnetic Properties of the 1-D Hubbard Model

1991 ◽  
Vol 05 (01n02) ◽  
pp. 3-30 ◽  
Author(s):  
J. Carmelo ◽  
P. Horsch ◽  
P.A. Bares ◽  
A.A. Ovchinnikov
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Low Temperature ◽  
Hubbard Model ◽  
Luttinger Liquid ◽  
Liquid Formulation ◽  
One Dimensional ◽  
Spin Excitations ◽  
Arbitrary Strength ◽  
The One

The Landau-Luttinger liquid formulation is used to investigate the physics of the one-dimensional Hubbard model in a magnetic field of arbitrary strength H. The low lying charge and spin excitations are studied. A novel branch of sound wave-like spin excitations arises for H>0. The low temperature thermodynamics is considered in some detail.

Low-Temperature Spin Fluctuations beyond Spin Waves

2015 ◽  
Vol 233-234 ◽  
pp. 20-24 ◽  
Author(s):  
N.B. Melnikov ◽  
B.I. Reser
Keyword(s):  
Low Temperature ◽  
Spin Fluctuation ◽  
Functional Integral ◽  
Spin Fluctuations ◽  
Integral Formalism ◽  
Ferromagnetic Metals ◽  
Wave Approximation ◽  
Dynamic Spin ◽  
Functional Integral Formalism ◽  
Temperature Dynamic

A simple low-temperature dynamic spin-fluctuation theory of ferromagnetic metals is developed. The theory is based on the functional integral formalism for the multiband Hubbard Hamiltonian and takes into account both single-site and nonlocal spin fluctuations. We show that our approach correctly reproduces the T3/2 law at low temperatures. The calculated results of magnetic properties for Fe and Fe0.65Ni0.35 Invar demonstrate that the approach works on a much wider temperature interval than the spin-wave approximation.

NMR-NQR Study of the Crossover from the Spin-Glass to the Superconducting Phase in La2-xSrxCuO4

1999 ◽  
Vol 13 (09n10) ◽  
pp. 1235-1240
Author(s):  
M.-H. Julien ◽  
P. Carretta ◽  
F. Borsa ◽  
A. Rigamonti
Keyword(s):  
Low Temperature ◽  
Spin Glass ◽  
Correlation Length ◽  
Superconducting Phase ◽  
Spin Fluctuations ◽  
Relaxation Rates ◽  
Slowing Down ◽  
Spin Glass Behavior ◽  
Spin Freezing ◽  
Glass Behavior

139 La and 63 Cu NQR relaxation rates are used to obtain insights on the effects of itinerant holes on the magnetic in-plane correlation length, for x ≤ 0.04 in La 2-x Sr x CuO 4. For these concentrations, corresponding to spin-glass behavior at low temperature, evidence for the microsegregation of holes along stripes is presented. Preliminary relaxation results for an amount of Sr doping leading to superconductivity are also presented and discussed in terms of the crossover from the spin-glass to the underdoped superconducting regime: for x = 0.06 a slowing down of spin fluctuations is evidenced and superconductivity is found to coexist with spin-freezing.

Contribution of spin fluctuations to the low-temperature resistivity and thermopower of YCo2

1998 ◽  
Vol 177-181 ◽  
pp. 1069-1070 ◽  
Author(s):  
A.T. Burkov ◽  
T. Nakama ◽  
T. Kohama ◽  
T. Shimoji ◽  
K. Shintani ◽  
...  
Keyword(s):  
Low Temperature ◽  
Spin Fluctuations ◽  
Temperature Resistivity

Electron spectral density of the half-filled Hubbard model in the atomic limit at finite temperature

Open Physics ◽  
2003 ◽  
Vol 1 (3) ◽  
Author(s):  
Sergei Ovchinnikov ◽  
Elena Shneyder
Keyword(s):  
Low Temperature ◽  
Spectral Density ◽  
Hubbard Model ◽  
Density Wave ◽  
Spin Density Wave ◽  
Long Range Order ◽  
Two Dimensional ◽  
Similar Form ◽  
Atomic Limit ◽  
Ordered State

AbstractWe have calculated the spectral function and density of states of halffilled two-dimensional Hubbard model in the Hubbard-I approximation assuming an antiferromagnetic long range order at low temperature and compared results to the QMC data. It occurs that calculated functions are in a qualitative agreement with the QMC one. We have also shown that Neel ordered state dispersion has the similar form to the spin density wave one.

scholarly journals The Thermopower and Resistivity of Nearly Magnetic Dilute Alloys

2021 ◽  
Author(s):  
◽  
Constantin Wassilieff
Keyword(s):  
Low Temperature ◽  
Spin Fluctuation ◽  
Residual Resistivity ◽  
Spin Fluctuations ◽  
Magnetic Alloy ◽  
Drag Effect ◽  
Glass Substrates ◽  
Dilute Alloys ◽  
Fluctuation Temperature ◽  
Impurity Sites

<p>In some nearly magnetic dilute alloys, in which the host and impurity are transition metals of similar electronic structure, the thermopower is observed to form a "giant" peak at about the spin fluctuation temperature Tsf deduced from resistivity measurements. Two explanations for these peaks have been postulated: the first is that the peaks are a diffusion thermopower component involving scattering off localized spin fluctuations (LSF) at the impurity sites; the second is that they are an LSF drag effect. We examine the thermopower and resistively of two nearly magnetic alloy systems: Rh(Fe) and Pt(Ni). In the first part of this thesis we describe measurements of the low temperature thermopower and resistivity of several Rh(Fe) alloys to clarify discrepancies in previous measurements and we show, by using a modified Nordheim-Gorter analysis, that the observed thermopower peaks are a diffusion and not a drag effect. In the second part of the thesis we describe measurements of the low temperature thermopower and resistivity of Pt (Ni), for which no previous data had been available. The Pt(Ni) samples are manufactured as thin, evaporated films on glass substrates. However, due to the difficulty encountered in controlling the very high residual resistivity of these samples, we are not able to draw definite conclusions regarding either the thermopower or the resistivity.</p>

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