Buscar
Mostrando ítems 1-10 de 2641
Thermal phase transition for some spin-boson models
(2013-09-01)
In this work we study two different spin-boson models. Such models are generalizations of the Dicke model, it means they describe systems of N identical two-level atoms coupled to a single-mode quantized bosonic field, ...
Insulator-to-metal transition driven by clustering of solitons in polyacetylene
(1997-03-15)
It's believed that the simple Su-Schrieffer-Heeger Hamiltonian can not predict the insulator to metal transition of transpolyacetylene (t-PA). The soliton lattice configuration at a doping level y=6% still has a semiconductor ...
Influence of phase transition on shock-induced spallation in nanocrystalline iron
(American Institute of Physics, 2015-11)
Intense shock waves may lead to spallation of the sample. Recent experiments show differences of shock spallation in iron depending on whether the samples underwent the pressure-induced bcc-hcp phase transformation or not. ...
Sensitivity to perturbations and quantum phase transition
(Amer Physical Soc, 2013-05-17)
The local density of states or its Fourier transform, usually called fidelity amplitude, are important measures of quantum irreversibility due to imperfect evolution. In this Rapid Communication we study both quantities ...
Q-deformed fermionic Lipkin model at finite temperature
(1997-08-15)
The interplay between temperature and q-deformation in the phase transition properties of many-body systems is studied in the particular framework of the collective q-deformed fermionic Lipkin model. It is shown that in ...
Structural, electronic, and magnetic entropy contributions of the orbital order-disorder transition in LaMnO(3)
(TAYLOR & FRANCIS LTD, 2011)
Measurements of X-ray diffraction, electrical resistivity, and magnetization are reported across the Jahn-Teller phase transition in LaMnO(3). Using a thermodynamic equation, we obtained the pressure derivative of the ...
Structural phase transitions of PbZr0.52Ti0.48O3 ceramic: An infrared spectroscopy study
(Taylor & Francis Ltd, 2006-01-01)
The recent discovery of a ferroelectric monoclinic phase in the PbZr1-xTixO3 (PZT) system attained the attention of several researchers due to the possibility of understanding the relationships between structural features ...
Metric-Space Approach for Distinguishing Quantum Phase Transitions in Spin-Imbalanced Systems
(Springer, 2018-10-01)
Metric spaces are characterized by distances between pairs of elements. Systems that are physically similar are expected to present smaller distances (between their densities, wave functions, and potentials) than systems ...
Ferroelectric phase transition in Pb0.60Sr0.40TiO3 thin films
(Elsevier B.V., 2004-10-15)
Polycrystalline Pb-0.Sr-60(0).40TiO3 thin films with the tetragonal perovskite structure were grown on platinum-coated silicon substrates by a chemical method. Raman results reveal that A1 (1 TO) symmetry modes, also known ...
In situ X-ray diffraction studies of phase transition in Pb1-x La x Zr0.40Ti0.60O3 ferroelectric ceramics
(TAYLOR & FRANCIS LTD, 2010)
The temperature dependence of the crystalline structure and the lattice parameters of Pb1-xLaxZr0.40Ti0.60O3 ferroelectric ceramic system with 0.00 x 0.21 was determined. The samples with x 0.11 show a cubic-to-tetragonal ...