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Full-Text Articles in Physics
Defect-Assisted Tunneling Electroresistance In Ferroelectric Tunnel Junctions, Konstantin Klyukin, L. L. Tao, Evgeny Y. Tsymbal, Vitaly Alexandrov
Defect-Assisted Tunneling Electroresistance In Ferroelectric Tunnel Junctions, Konstantin Klyukin, L. L. Tao, Evgeny Y. Tsymbal, Vitaly Alexandrov
Evgeny Tsymbal Publications
Recent experimental results have demonstrated ferroelectricity in thin films of SrTiO3 induced by antisite TiSr defects. This opens a possibility to use SrTiO3 as a barrier layer in ferroelectric tunnel junctions (FTJs)—emerging electronic devices promising for applications in nanoelectronics. Here using density functional theory combined with quantum-transport calculations applied to a prototypical Pt/SrTiO3/Pt FTJ, we demonstrate that the localized in-gap energy states produced by the antisite TiSr defects are responsible for the enhanced electron tunneling conductance which can be controlled by ferroelectric polarization. Our tight-binding modeling, which takes into account multiple defects, shows that …
Effects Of B And C Doping On Tunneling Magnetoresistance In Cofe/Mgo Magnetic Tunnel Junctions, Andy Paul Chen, John D. Burton, Evgeny Y. Tsymbal, Yuan Ping Feng, Jingsheng Chen
Effects Of B And C Doping On Tunneling Magnetoresistance In Cofe/Mgo Magnetic Tunnel Junctions, Andy Paul Chen, John D. Burton, Evgeny Y. Tsymbal, Yuan Ping Feng, Jingsheng Chen
Evgeny Tsymbal Publications
Using density-functional theory calculations, we investigate the dominant defects formed by boron (B) and carbon (C) impurities in a CoFe/MgO/CoFe magnetic tunnel junction (MTJ) and their influence on conductivity and tunneling magnetoresistance (TMR). We find that, in the O-poor conditions relevant to experiment, B forms the substitutional defect BCo and C forms the interstitial site Ci at the CoFe/MgO interface. The C-doped MTJ is predicted to have a significantly higher TMR than the B-doped MTJ. This is due to interface state densities associated with the majority spin Δ1-symmetry bands being more heavily suppressed by the B …
Dissipation Effects In Schrödinger And Quantal Density Functional Theories Of Electrons In An Electromagnetic Field, Xiao-Yin Pan, Viraht Sahni
Dissipation Effects In Schrödinger And Quantal Density Functional Theories Of Electrons In An Electromagnetic Field, Xiao-Yin Pan, Viraht Sahni
Publications and Research
Dissipative effects arise in an electronic system when it interacts with a time-dependent environment. Here, the Schrödinger theory of electrons in an electromagnetic field including dissipative effects is described from a new perspective. Dissipation is accounted for via the effective Hamiltonian approach in which the electron mass is time-dependent. The perspective is that of the individual electron: the corresponding equation of motion for the electron or time-dependent differential virial theorem—the ‘Quantal Newtonian’ second law—is derived. According to the law, each electron experiences an external field comprised of a binding electric field, the Lorentz field, and the electromagnetic field. In addition, …