3,550 research outputs found
Interfaces of correlated electron systems: Proposed mechanism for colossal electroresistance
Mott's metal-insulator transition at an interface due to band bending is
studied by the density matrix renormalization group (DMRG). We show that the
result can be recovered by a simple modification of the conventional Poisson's
equation approach used in semi-conductor heterojunctions. A novel mechanism of
colossal electroresistance is proposed, which incorporates the hysteretic
behavior of the transition in higher dimensions.Comment: 5 pages, 3 figures, title change
Periodicity-dependence of the ferroelectric properties in BiFeO3/SrTiO3 multiferroic superlattices
Artificial superlattices of (BiFeO3)m(SrTiO3)m (m= 1 to 10 unit cells)
consisting of multiferroic BiFeO3 and insulating SrTiO3 layers were fabricated
on (100)-oriented SrTiO3 substrates by pulsed laser ablation. The remnant
polarization and leakage current behavior were studied varying the periodicity
(8-80A) of the superlattice. The leakage current was reduced by few orders of
magnitude on increase of periodicity compared to single layer BiFeO3 thin
films. Reduced leakage and intrinsic polarization hysteresis was observed and
was confirmed by PUND analysis for periodicities in the range 20-60A. The
leakage current was observed to be dominated by space charge limited conductionComment: Submitted to Applied Physics Letter
Resistive switching in ultra-thin La0.7Sr0.3MnO3 / SrRuO3 superlattices
Superlattices may play an important role in next generation electronic and
spintronic devices if the key-challenge of the reading and writing data can be
solved. This challenge emerges from the coupling of low dimensional individual
layers with macroscopic world. Here we report the study of the resistive
switching characteristics of a of hybrid structure made out of a superlattice
with ultrathin layers of two ferromagnetic metallic oxides, La0.7Sr0.3MnO3
(LSMO) and SrRuO3 (SRO). Bipolar resistive switching memory effects are
measured on these LSMO/SRO superlattices, and the observed switching is
explainable by ohmic and space charge-limited conduction laws. It is evident
from the endurance characteristics that the on/off memory window of the cell is
greater than 14, which indicates that this cell can reliably distinguish the
stored information between high and low resistance states. The findings may
pave a way to the construction of devices based on nonvolatile resistive memory
effects
Charge Carrier Transport in Metal Phthalocyanine Based Disordered Thin Films
The charge carrier transport in metal phthallocyanine based disordered thin
films has been investigated. Charge carrier mobility in these disordered thin
films strongly depends on the electric field and temperature due to hopping
conduction. The applicability of two different Gaussian disorder models has
been compared and evaluated for charge carrier transport using simple
experimental results and based on our extensive analysis, it has been found
that spatial and energetic correlation is important in explaining the
electrical transport in these organic semiconductors
Multicentric carcinoma: a report of four cases and some gynaecological and surgical aspects
No Abstrac
An Analytic Solution of Hydrodynamic Equations with Source Terms in Heavy Ion Collisions
The energy and baryon densities in heavy ion collisions are estimated by
analytically solving a 1+1 dimensional hydrodynamical model with source terms.
Particularly, a competition between the energy and baryon sources and the
expansion of the system is discussed in detail.Comment: LaTeX2e, 7 pages, 4 postscript figures, submitted to Int. J. Mod.
Phys.
Effect of excited states and applied magnetic fields on the measured hole mobility in an organic semiconductor
Copyright 2010 by the American Physical Society. Article is available at
Self-consistent model of unipolar transport in organic semiconductor diodes: accounting for a realistic density-of-states distribution
A self-consistent, mean-field model of charge-carrier injection and unipolar
transport in an organic semiconductor diode is developed utilizing the
effective transport energy concept and taking into account a realistic
density-of-states distribution as well as the presence of trap states in an
organic material. The consequences resulting from the model are discussed
exemplarily on the basis of an indium tin oxide/organic semiconductor/metallic
conductor structure. A comparison of the theory to experimental data of a
unipolar indium tin oxide/poly-3-hexyl-thiophene/Al device is presented.Comment: 6 pages, 2 figures; to be published in Journal of Applied Physic
- …