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Physics

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University of Nebraska - Lincoln

Evgeny Tsymbal Publications

2009

Articles 1 - 9 of 9

Full-Text Articles in Physical Sciences and Mathematics

Magnetoelectric Effect At The Srruo3/Batio3 (001) Interface: An Ab Initio Study, Manish K. Niranjan, John D. Burton, Julian P. Velev, Sitaram Jaswal, Evgeny Y. Tsymbal Aug 2009

Magnetoelectric Effect At The Srruo3/Batio3 (001) Interface: An Ab Initio Study, Manish K. Niranjan, John D. Burton, Julian P. Velev, Sitaram Jaswal, Evgeny Y. Tsymbal

Evgeny Tsymbal Publications

Ferromagnet/ferroelectric interface materials have emerged as structures with strong magnetoelectric coupling that may exist due to unconventional physical mechanisms. Here we present a first-principles study of the magnetoelectric effect at the ferromagnet/ferroelectric SrRuO3 /BaTiO3 (001) interface. We find that the exchange splitting of the spin-polarized band structure, and therefore the magnetization, at the interface can be altered substantially by reversal of the ferroelectric polarization in the BaTiO3. These magnetoelectric effects originate from the screening of polarization charges at the SrRuO3 /BaTiO3 interface and are consistent with the Stoner model for itinerant magnetism.

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Tunneling Electroresistance In Ferroelectric Tunnel Junctions With A Composite Barrier, M. Ye. Zhuravlev, Yong Wang, S. Maekawa, Evgeny Y. Tsymbal Aug 2009

Tunneling Electroresistance In Ferroelectric Tunnel Junctions With A Composite Barrier, M. Ye. Zhuravlev, Yong Wang, S. Maekawa, Evgeny Y. Tsymbal

Evgeny Tsymbal Publications

Tunneling electroresistance (TER) effect is the change in the electrical resistance of a ferroelectric tunnel junction (FTJ) associated with polarization reversal in the ferroelectric barrier layer. Here we predict that a FTJ with a composite barrier that combines a functional ferroelectric film and a thin layer of a nonpolar dielectric can exhibit a significantly enhanced TER. Due to the change in the electrostatic potential with polarization reversal, the nonpolar dielectric barrier acts as a switch that changes its barrier height from a low to high value. The predicted values of TER are giant and indicate that the resistance of the …

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Quantum Nature Of Two-Dimensional Electron Gas Confinement At Laalo3=Srtio3 Interfaces, Karolina Janicka, Julian P. Velev, Evgeny Y. Tsymbal Mar 2009

Quantum Nature Of Two-Dimensional Electron Gas Confinement At Laalo3=Srtio3 Interfaces, Karolina Janicka, Julian P. Velev, Evgeny Y. Tsymbal

Evgeny Tsymbal Publications

We perform density functional calculations to understand the mechanism controlling the confinement width of the two-dimensional electron gas (2DEG) at LaAlO3/SrTiO3 interfaces. We find that the 2DEG confinement can be explained by the formation of metal induced gap states (MIGS) in the band gap of SrTiO3. These states are formed as the result of quantum-mechanical tunneling of the charge created at the interface due to electronic reconstruction. The attenuation length of the MIGS into the insulator is controlled by the lowest-decay-rate evanescent states of SrTiO3, as determined by its complex band structure. Our …

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First-Principles Studies Of A Two-Dimensional Electron Gas At The Interface In Ferroelectric Oxide Heterostructures, Yong Wang, Manish K. Niranjan, Sitaram Jaswal, Evgeny Y. Tsymbal Jan 2009

First-Principles Studies Of A Two-Dimensional Electron Gas At The Interface In Ferroelectric Oxide Heterostructures, Yong Wang, Manish K. Niranjan, Sitaram Jaswal, Evgeny Y. Tsymbal

Evgeny Tsymbal Publications

The discovery of a two-dimensional electron gas (2DEG) at the interface between two insulating oxides has recently stimulated intense research activity in this field. The 2DEG has unique properties that are promising for applications in all-oxide electronic devices.

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Universality Of The Surface Magnetoelectric Effect In Half-Metals, Chun-Gang Duan, Ce-Wen Nan, Sitaram S. Jaswal, Evgeny Y. Tsymbal Jan 2009

Universality Of The Surface Magnetoelectric Effect In Half-Metals, Chun-Gang Duan, Ce-Wen Nan, Sitaram S. Jaswal, Evgeny Y. Tsymbal

Evgeny Tsymbal Publications

An electric field applied to a ferromagnetic metal produces a surface magnetoelectric effect originating from the spin-dependent screening of the electric field which results in a change in the surface magnetization of the ferromagnet.

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Oxide Tunnel Junctions Supporting A Two-Dimensional Electron Gas, John D. Burton, Julian P. Velev, Evgeny Y. Tsymbal Jan 2009

Oxide Tunnel Junctions Supporting A Two-Dimensional Electron Gas, John D. Burton, Julian P. Velev, Evgeny Y. Tsymbal

Evgeny Tsymbal Publications

The discovery of a two-dimensional electron gas (2DEG) at the interface between insulating oxides has led to a well-deserved level of excitement due to possible applications as “in-plane” all-oxide nanoelectronics. Here we expand the range of possibilities to the realm of “out-of-plane” nanoelectronics by examining such all-oxide heterostructures as barriers in tunnel junctions.

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Prediction Of A Spin-Polarized Two-Dimensional Electron Gas At The Laalo3/Euo(001) Interface, Yong Wang, Manish K. Niranjan, John D. Burton, Joonhee M. An, Kirill D. Belashchenko, Evgeny Y. Tsymbal Jan 2009

Prediction Of A Spin-Polarized Two-Dimensional Electron Gas At The Laalo3/Euo(001) Interface, Yong Wang, Manish K. Niranjan, John D. Burton, Joonhee M. An, Kirill D. Belashchenko, Evgeny Y. Tsymbal

Evgeny Tsymbal Publications

First-principles calculations predict the existence of a spin-polarized two-dimensional electron gas (2DEG) at the LaO/EuO interface in a LaAlO3/EuO(001) heterostructure. This polar interface favors electron doping into the Eu-5d conduction bands resulting in a 2DEG formed at the interface.

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Prediction Of Electrically Induced Magnetic Reconstruction At The Manganite/Ferroelectric Interface, John D. Burton, Evgeny Y. Tsymbal Jan 2009

Prediction Of Electrically Induced Magnetic Reconstruction At The Manganite/Ferroelectric Interface, John D. Burton, Evgeny Y. Tsymbal

Evgeny Tsymbal Publications

The control of magnetization via the application of an electric field, known as magnetoelectric coupling, is among the most fascinating and active research areas today. In addition to fundamental scientific interest, magnetoelectric effects may lead to new device concepts for data storage and processing. There are several known mechanisms for magnetoelectric coupling that include intrinsic effects in single-phase materials, strain-induced coupling in two-phase composites, and electronically driven effects at interfaces. Here we explore a different type of magnetoelectric effect at a ferromagnetic-ferroelectric interface: magnetic reconstruction induced by switching of electric polarization.

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Prediction Of A Switchable Two-Dimensional Electron Gas At Ferroelectric Oxide Interfaces, Manish K. Niranjan, Yong Wang, Sitaram S. Jaswal, Evgeny Y. Tsymbal Jan 2009

Prediction Of A Switchable Two-Dimensional Electron Gas At Ferroelectric Oxide Interfaces, Manish K. Niranjan, Yong Wang, Sitaram S. Jaswal, Evgeny Y. Tsymbal

Evgeny Tsymbal Publications

The demonstration of a quasi-two-dimensional electron gas (2DEG) in LaAlO3=SrTiO3 heterostructures has stimulated intense research activity in recent years. The 2DEG has unique properties that are promising for applications in all-oxide electronic devices. For such applications it is desirable to have the ability to control 2DEG properties by external stimulus. Here, based on first-principles calculations we predict that all-oxide heterostructures incorporating ferroelectric constituents, such as KNbO3=ATiO3 (A = Sr, Ba, Pb), allow creating a 2DEG switchable between two conduction states by ferroelectric polarization reversal. The effect occurs due to the screening charge at …

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