scholarly journals Local Enhancement of Antiferromagnetic Correlations by Nonmagnetic Impurities

1997 ◽  
Vol 78 (18) ◽  
pp. 3563-3566 ◽  
Author(s):  
George Balster Martins ◽  
Markus Laukamp ◽  
José Riera ◽  
Elbio Dagotto
1998 ◽  
Vol 12 (29n31) ◽  
pp. 3330-3334 ◽  
Author(s):  
Y. Sidis ◽  
P. Bourges ◽  
B. Hennion ◽  
R. Villeneuve ◽  
G. Collin ◽  
...  

Inelastic neutron scattering measurements have been carried out on a YBa2(Cu0.98-Zn0.02)3O 6+x single crystal in both underdoped (x = 0.7) and overdoped (x = 0.97) regimes. In the zinc substituted system, spin dynamics is drastically changed in respect to the pure compound: (i) the "resonance peak" almost vanishes, (ii) the spin gap is filled, (iii) new antiferromagnetic excitations are found at low energy. These new magnetic fluctuations, which persist in the normal state, account for a local enhancement of AF correlations around nonmagnetic impurities. Besides, it is worth emphasizing that features, not directly related to superconductivity, i.e., the contribution to the spin dynamics apart from the resonance peak and the "spin pseudo-gap" observed in the underdoped regime above T c , coexist with the new low energy magnetic fluctuations.


2000 ◽  
Vol 14 (29n31) ◽  
pp. 3374-3379
Author(s):  
N. BULUT ◽  
U. YAZ

The NMR and neutron scattering experiments on YBa 2 Cu 3 O 7 with Li and Zn impurities are compared using a simple framework exhibiting short-range antiferromagnetic correlations. The model parameters are determined by fitting the NMR rate [Formula: see text] of the pure system, and the effective impurity potential is approximated by a static extended form. The results of the calculations are compared with the experimental data, and their implications are discussed.


1998 ◽  
Vol 57 (17) ◽  
pp. 10755-10769 ◽  
Author(s):  
Markus Laukamp ◽  
George Balster Martins ◽  
Claudio Gazza ◽  
André L. Malvezzi ◽  
Elbio Dagotto ◽  
...  

2020 ◽  
Vol 102 (18) ◽  
Author(s):  
Sumin Lim ◽  
Sejun Park ◽  
Soonchil Lee ◽  
Kisoo Park ◽  
Hasung Sim ◽  
...  

Author(s):  
Hezhen Hu ◽  
Wengang Zhou ◽  
Junfu Pu ◽  
Houqiang Li

Sign language recognition (SLR) is a challenging problem, involving complex manual features (i.e., hand gestures) and fine-grained non-manual features (NMFs) (i.e., facial expression, mouth shapes, etc .). Although manual features are dominant, non-manual features also play an important role in the expression of a sign word. Specifically, many sign words convey different meanings due to non-manual features, even though they share the same hand gestures. This ambiguity introduces great challenges in the recognition of sign words. To tackle the above issue, we propose a simple yet effective architecture called Global-Local Enhancement Network (GLE-Net), including two mutually promoted streams toward different crucial aspects of SLR. Of the two streams, one captures the global contextual relationship, while the other stream captures the discriminative fine-grained cues. Moreover, due to the lack of datasets explicitly focusing on this kind of feature, we introduce the first non-manual-feature-aware isolated Chinese sign language dataset (NMFs-CSL) with a total vocabulary size of 1,067 sign words in daily life. Extensive experiments on NMFs-CSL and SLR500 datasets demonstrate the effectiveness of our method.


1974 ◽  
Vol 17 (3-4) ◽  
pp. 223-246 ◽  
Author(s):  
G. Bongi ◽  
R. Fl�kiger ◽  
A. Treyvaud ◽  
�. Fischer ◽  
H. Jones ◽  
...  

ACS Nano ◽  
2017 ◽  
Vol 11 (12) ◽  
pp. 12553-12561 ◽  
Author(s):  
Andrea Torchi ◽  
Federica Simonelli ◽  
Riccardo Ferrando ◽  
Giulia Rossi

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