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Faculty Publications, Department of Physics and Astronomy

2011

Articles 1 - 5 of 5

Full-Text Articles in Physics

Large Magnetoelectric Effect In Ferroelectric/Piezomagnetic Heterostructures, Pavel Lukashev, Kirill D. Belashchenko, Renat F. Sabirianov Jan 2011

Large Magnetoelectric Effect In Ferroelectric/Piezomagnetic Heterostructures, Pavel Lukashev, Kirill D. Belashchenko, Renat F. Sabirianov

Faculty Publications, Department of Physics and Astronomy

We present results of the first-principles calculations on the large magnetoelectric effect in ferroelectric/ piezomagnetic multilayers. We consider thin-film layered heterostructures of typical ferroelectrics, such as PbTiO3, with piezomagnetic (PzM) Mn-based antiperovskites, such as Mn3GaN. The atomic displacements induced by the FE polarization as well as mechanical stress at the interface break the triangular magnetic symmetry of the PzM phase producing net magnetization in the system. The induced magnetization can be controlled by changing the direction of polarization in the ferroelectric phase. Our calculations show that reversal of the polarization results in change of the net magnetization in the ...


Effective Mass Of Electrons And Holes In Bilayer Graphene: Electron-Hole Asymmetry And Electron-Electron Interaction, K. Zou, X. Hong, J. Zhu Jan 2011

Effective Mass Of Electrons And Holes In Bilayer Graphene: Electron-Hole Asymmetry And Electron-Electron Interaction, K. Zou, X. Hong, J. Zhu

Faculty Publications, Department of Physics and Astronomy

Precision measurements of the effective mass m* in high-quality bilayer graphene using the temperature dependence of the Shubnikov–de Haas oscillations are reported. In the density range 0.7 × 1012 < n < 4.1 × 1012 cm−2, both the hole mass m*h and the electron mass m*e increase with increasing density, demonstrating the hyperbolic nature of the bands. The hole mass m*h is approximately 20–30% larger than the electron mass m*e . Tight-binding calculations provide a good description of the electron-hole asymmetry and yield an accurate measure of the interlayer hopping parameter v4 = 0.063. Both m*h and ...


Experimental Observation Of Time-Delays Associated With Electric Matteucci–Pozzi Phase Shifts, Shawn A. Hilbert, Adam Caprez, Herman Batelaan Jan 2011

Experimental Observation Of Time-Delays Associated With Electric Matteucci–Pozzi Phase Shifts, Shawn A. Hilbert, Adam Caprez, Herman Batelaan

Faculty Publications, Department of Physics and Astronomy

In 1985, Matteucci and Pozzi (1985 Phys. Rev. Lett. 54 2469) demonstrated the presence of a quantum mechanical phase shift for electrons passing a pair of oppositely charged biprism wires. For this experimental arrangement no forces deflect the electrons. Consequently, the result was reported as a non-local type-2 Aharonov–Bohm effect. Boyer (2002 Found. Phys. 32 41–50; 1987 Nuovo Cimento B 100 685–701) showed theoretically that the Matteucci–Pozzi effect could be associated with a time delay caused by a classical force. We present experimental data that confirm the presence of a time delay. This result is in ...


Transverse Quantum Stern–Gerlach Magnets For Electrons, Scot Mcgregor, Roger Bach, Herman Batelaan Jan 2011

Transverse Quantum Stern–Gerlach Magnets For Electrons, Scot Mcgregor, Roger Bach, Herman Batelaan

Faculty Publications, Department of Physics and Astronomy

In the Stern–Gerlach experiment, silver atoms were separated according to their spin state (Gerlach and Stern 1922 Z. Phys. 9 353–355). This experiment demonstrates the quantization of spin and relies on the classical description of motion. However, so far, no design has led to a functional Stern–Gerlach magnet for free electrons. Bohr and Pauli showed in the 1930 Solvay conference that Stern–Gerlach magnets for electrons cannot work, at least if the design is based on classical trajectories (Pauli W 1932 Proc. of the 6th Solvay Conf. 2 (1930) (Brussels: Gauthier-Villars) pp 183–86, 217–20, 275 ...


Quantum Description And Properties Of Electrons Emitted From Pulsed Nanotip Electron Sources, Pavel Lougovski, Herman Batelaan Jan 2011

Quantum Description And Properties Of Electrons Emitted From Pulsed Nanotip Electron Sources, Pavel Lougovski, Herman Batelaan

Faculty Publications, Department of Physics and Astronomy

We present a quantum calculation of the electron degeneracy for electron sources. We explore quantum interference of electrons in the temporal and spatial domain and demonstrate how it can be utilized to characterize a pulsed electron source. We estimate effects of Coulomb repulsion on two-electron interference and show that currently available nano tip pulsed electron sources operate in the regime where the quantum nature of electrons can be made dominant.