Monte Carlo simulations of the four-dimensionalXYspin glass at low temperatures

AbstractNegative capacitance in BaTiO3/SrTiO3 superlattices is investigated by Monte Carlo simulations in an atomistic effective Hamiltonian model, using fluctuation formulas for responses to the local macroscopic field that incorporates depolarizing fields. We show that epitaxial strain can tune the negative capacitance of the BaTiO3 ferroelectric layer and the overall capacitance of the system. In addition, we predict and explain an original switching of the negative capacitance from the BaTiO3 layer to the SrTiO3 layer at low temperatures for intermediate strains.

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TRANSIT TIME DISTRIBUTION AND MOBILITY IN MONTE CARLO SIMULATIONS OF THE GAUSSIAN DISORDER MODEL

International Journal of Modern Physics B ◽

10.1142/s0217979213500100 ◽

2013 ◽

Vol 27 (05) ◽

pp. 1350010 ◽

Cited By ~ 1

Author(s):

SUNIL KIM ◽

JOONHYUN YEO ◽

CHAN IM

Keyword(s):

Monte Carlo ◽

Monte Carlo Simulations ◽

Transit Time ◽

Low Temperatures ◽

Heavy Tail ◽

Charge Carriers ◽

Dispersive Transport ◽

Transit Times ◽

Mobility Of Charge Carriers ◽

Gaussian Disorder Model

We study the distribution of transit times in Monte Carlo simulations of the Gaussian disorder model (GDM). The GDM is one of the most successful models to describe the charge transport in random organic materials. The transit time is the time it takes for a charge carrier to travel across a sample. We find that the distribution of transit times over many charge carriers and over different realizations of Gaussian energies shows a heavy tail in the long time limit at low temperatures. This heavy tail can be described by a power law with an exponent that depends on temperature. This sets a limitation on the calculation of mobility of charge carriers using an average transit time at low temperatures. We discuss the implication of these results on dispersive transport.

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Low-voltage EDS of magnesium ferrite Dendrites in a FEG-SEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100164854 ◽

1996 ◽

Vol 54 ◽

pp. 478-479

Author(s):

Matthew T. Johnson ◽

Ian M. Anderson ◽

Jim Bentley ◽

C. Barry Carter

Keyword(s):

Monte Carlo ◽

Quantitative Analysis ◽

Monte Carlo Simulations ◽

Cross Section ◽

Spatial Resolution ◽

Low Voltage ◽

Magnesium Ferrite ◽

X Ray ◽

Interaction Volume ◽

Ferrite Spinel

Energy-dispersive X-ray spectrometry (EDS) performed at low (≤ 5 kV) accelerating voltages in the SEM has the potential for providing quantitative microanalytical information with a spatial resolution of ∼100 nm. In the present work, EDS analyses were performed on magnesium ferrite spinel [(MgxFe1−x)Fe2O4] dendrites embedded in a MgO matrix, as shown in Fig. 1. spatial resolution of X-ray microanalysis at conventional accelerating voltages is insufficient for the quantitative analysis of these dendrites, which have widths of the order of a few hundred nanometers, without deconvolution of contributions from the MgO matrix. However, Monte Carlo simulations indicate that the interaction volume for MgFe2O4 is ∼150 nm at 3 kV accelerating voltage and therefore sufficient to analyze the dendrites without matrix contributions.Single-crystal {001}-oriented MgO was reacted with hematite (Fe2O3) powder for 6 h at 1450°C in air and furnace cooled. The specimen was then cleaved to expose a clean cross-section suitable for microanalysis.

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