scholarly journals Measuring Entropy and Short-Range Correlations in the Two-Dimensional Hubbard Model

2017 ◽  
Vol 7 (3) ◽  
Author(s):  
E. Cocchi ◽  
L. A. Miller ◽  
J. H. Drewes ◽  
C. F. Chan ◽  
D. Pertot ◽  
...  
Keyword(s):  
Hubbard Model ◽  
Short Range ◽  
Two Dimensional ◽  
Short Range Correlations

scholarly journals Magnetic Order, Spin Waves and Fluctuations in the Triangular Antiferromagnet La2Ca2MnO7

SPIN ◽  
2015 ◽  
Vol 05 (02) ◽  
pp. 1540001 ◽  
Author(s):  
P. Dalmas de Réotier ◽  
C. Marin ◽  
A. Yaouanc ◽  
T. Douce ◽  
A. Sikora ◽  
...  
Keyword(s):  
Specific Heat ◽  
Spin Wave ◽  
Short Range ◽  
Magnetic Order ◽  
Inelastic Neutron Scattering ◽  
Spin Fluctuations ◽  
Scattering Data ◽  
Two Dimensional ◽  
Spin Wave Gap ◽  
Short Range Correlations

We report magnetic susceptibility, specific heat and muon spin relaxation (μSR) experiments on the triangular antiferromagnet La 2 Ca 2 MnO 7 which develops a genuine two-dimensional (2D), three-sublattice [Formula: see text] magnetic order below T N = 2.8 K. From the susceptibility and specific heat an estimate of the exchange interaction is derived. A value for the spin-wave gap is obtained from the latter data. The analysis of a previously reported inelastic neutron scattering data yields values for the exchange and spin-wave gap compatible with the results obtained from macroscopic measurements. An appreciable entropy is still missing at 10 K that may be ascribed to intense short-range correlations. The critical paramagnetic fluctuations extend far above T N , and can be partly understood in terms of two-dimensional spin-wave excitations. While no spontaneous μSR field is observed below T N , persistent spin dynamics is found. Short-range correlations are detected in this temperature range. Their relation to a possible molecular spin substructure and the observed exotic spin fluctuations is discussed.

Short-range correlations in two-dimensional liquid crystals

1975 ◽  
Vol 11 (2) ◽  
pp. 713-720 ◽  
Author(s):  
Sudip Chakravarty ◽  
Chia-Wei Woo
Keyword(s):  
Liquid Crystals ◽  
Short Range ◽  
Two Dimensional ◽  
Short Range Correlations
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