Phase transition of the fcc multilayer films with nearest neighbor and next-nearest neighbor interactions

2006 ◽  
Vol 139 (1) ◽  
pp. 40-44 ◽  
Author(s):  
Liqin Jiang ◽  
Qian Feng ◽  
Yanmin Yang ◽  
Zhigao Chen ◽  
Zhigao Huang
Keyword(s):  
Phase Transition ◽  
Nearest Neighbor ◽  
Multilayer Films

Phase Transition of C5H5 NHSbBr4 Having a Hypervalent Bond: A 2H NMR and X-Ray Diffraction Study [Phase Transition of C5H5NHSbBr4]

1996 ◽  
Vol 51 (5-6) ◽  
pp. 739-744
Author(s):  
K. Yamada ◽  
T. Ohtani ◽  
S. Shirakawa ◽  
H. Ohki ◽  
T. Okuda ◽  
...  
Keyword(s):  
Phase Transition ◽  
Nearest Neighbor ◽  
Study Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Line Shape Analysis ◽  
Deuterated Analog ◽  
Librational Motion ◽  
Diffraction Patterns

Abstract The second order phase transition at 253 K of pyridinium tetrabromoantimonate(III), C5H5NHSbBr4 , has been characterized by means of X-ray diffraction and 2H NMR. As was suggested from the 81Br NQR spectra, the Rietveld refinements of the X-ray diffraction patterns at 297 K and 116 K confirm the structural change of the anion from SbBr-4 to SbBr3 • Br-. The line shape analysis of the 2H NMR using the deuterated analog revealed that the librational amplitude of the pyridinium ring about the axis normal to the plane increased with temperature and its rms amplitude reaching ca. 25° at Tc . The librational motion may induce the phase transition breaking the hydrogen bonds of the type N-H … Br. However, nearest-neighbor 2π/6 jump or reorientation such as seen in benzene were not observed even at 350 K.

PRESSURE INDUCED PHASE TRANSITION (B3–B1) AND ELASTIC PROPERTIES OF II–VI ZnSe SEMICONDUCTORS

2012 ◽  
Vol 26 (14) ◽  
pp. 1250077
Author(s):  
DINESH VARSHNEY
Keyword(s):  
Phase Transition ◽  
Nearest Neighbor ◽  
Electron Shell ◽  
Phenomenological Approach ◽  
Interionic Interaction ◽  
Transition Pressure ◽  
Phase Transition Pressure ◽  
Reported Data ◽  
Three Body ◽  
Vdw Interaction

We evolve an effective interionic interaction potential (EIoIP) to investigate the pressure induced phase transitions from Zinc blende (B3) to Rocksalt (B1) structure in ZnSe semiconductor. The developed potential consists of the long-range Coulomb and three-body interactions (TBI) and the Hafemeister and Flygare type short-range (SR) overlap repulsion extended upto the second neighbor ions and the van der Waals (vdW) interaction. The three-body interactions arise from the electron-shell deformation when the nearest-neighbor ions overlap and has been employed for detailed studies of pressure-induced phase-transition behavior of ZnSe semiconductors. Our calculated value of the phase transition pressure (Pt) is higher and the magnitude of the discontinuity in volume at the transition pressure is consistent with reported data. The variation of second-order elastic constants with pressure resembles that observed in some binary semiconductors. It is inferred that the vdW interaction is effective in obtaining the Debye temperature, Gruneisen parameter, thermal expansion coefficient and compressibility. It is argued that the model with TBI (model II) has yielded somewhat more realistic predictions of the phase-transition and high-pressure behavior as compared to usual two-body potentials (model I) based on phenomenological approach.

Detecting topological phase transition in 1D superconducting systems with next nearest neighbor hopping

2014 ◽  
Vol 12 (1) ◽  
pp. 015202 ◽  
Author(s):  
Ling-Li Zhu ◽  
Qian Huang ◽  
Hui-Lin Dai ◽  
Cui Kong ◽  
Yu-lin Feng ◽  
...  
Keyword(s):  
Phase Transition ◽  
Nearest Neighbor ◽  
Topological Phase ◽  
Topological Phase Transition

Phase Transition in 2D Anisotropic Ising Model with Next-Nearest Neighbor Interactions in a Magnetic Field

SPIN ◽  
2018 ◽  
Vol 08 (03) ◽  
pp. 1850010
Author(s):  
D. Farsal ◽  
M. Badia ◽  
M. Bennai
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Phase Diagram ◽  
Monte Carlo ◽  
Magnetic Susceptibility ◽  
Critical Temperature ◽  
Ising Model ◽  
Nearest Neighbor ◽  
Two Dimensional ◽  
The Magnetic Field

The critical behavior at the phase transition of the ferromagnetic two-dimensional anisotropic Ising model with next-nearest neighbor (NNN) couplings in the presence of the field is determined using mainly Monte Carlo (MC) method. This method is used to investigate the phase diagram of the model and to verify the existence of a divergence at null temperature which often appears in two-dimensional systems. We analyze also the influence of the report of the NNN interactions [Formula: see text] and the magnetic field [Formula: see text] on the critical temperature of the system, and we show that the critical temperature depends on the magnetic field for positive values of the interaction. Finally, we have investigated other thermodynamical qualities such as the magnetic susceptibility [Formula: see text]. It has been shown that their thermal behavior depends qualitatively and quantitatively on the strength of NNN interactions and the magnetic field.

scholarly journals Structural Study of Ferroelectric Phase Transition of Sn-doped SrTiO3

2014 ◽  
Vol 70 (a1) ◽  
pp. C61-C61 ◽  
Author(s):  
Hirofumi Kasatani ◽  
Shoichiro Suzuki ◽  
Akira Ando ◽  
Eisuke Magome ◽  
Chikako Moriyoshi ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Local Structure ◽  
Ferroelectric Phase Transition ◽  
Nearest Neighbor ◽  
Ferroelectric Phase ◽  
Rietveld Analysis ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray

Recently, ferroelectricity was discovered in Sn-doped SrTiO3 (abbreviated by SSTO), in which Sr-atom was substituted by a few percent Sn-atom[1]. The ferroelctricity of SSTO was confirmed by means of the appearance of the dielectric anomaly, that reached several thousands and the clear D-E hysteresis loop in low temperature phase. In order to clarify the mechanism of ferroelectric phase transition of SSTO from the viewpoint of the crystal structure, we investigated the average crystal structure and the local structure around the substitutional Sn-atom of SSTO10 (10% Sn concentration, ferroelectric phase transition temperature 180K) by means of synchrotron-radiation powder X-ray diffraction and transmission XAFS spectrum of Sn:K-edge, respectively. From the results of MEM/Rietveld analysis of powder X-ray diffraction data, it was obtained that crystal structure of paraelectric phase of SSTO10 was cubic perovskite structure with the disorder state of Sn-atom. In ferroelectric phase, the crystal system was tetragonal, which was similar in structure to tetragonal ferroelectric structure of BaTiO3, and Sn-atom was order state. XAFS study revealed that the valence of Sn-ion was +2 charge and the local structure of Sn-atom was seemed as being the self-insistent state of SnO crystal structure. However, strangely, the coordination number of the nearest neighbor atom, that is O-atom, was 2 instead of 4. This is a mystery result and we have been analyzing. We have considered that the ferroelectricity of SSTO is induced by the distortion around the subsitituional Sn-atom. At the meeting, we are planning to discuss the precise crystal structure and the mechanism of the ferroelectric phase transition of SSTO.

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