283 research outputs found
Giant Effective G -factor In Pbx Eu1-x Te Epitaxial Films
No full textWe investigated Pbx Eu1-x Te films with x≤0.2 by magneto-optical measurements. For x∼0.01, the optical emission is similar to high quality EuTe films with two narrow lines attributed to excitonic recombinations associated with magnetic polarons. For increasing x, the emission becomes dominated by a broader lower energy band, which is very efficient as compared to the binary emission. The magneto-optical properties of the ternary films show various similarities with EuTe results, such as quenchings at similar temperatures and magnetic fields. Most remarkably, they also present a giant effective g -factor that makes this material a strong candidate for spintronic applications. © 2008 American Institute of Physics.933Mauger, A., Godart, C., (1986) Phys. Rep., 141, p. 51Masset, F., (1971) Phys. Rev. B, 3, p. 2364Akimoto, R., Kobayashi, M., Suzuki, T., (1994) J. Phys. Soc. Jpn., 63, p. 4616Heiss, W., Kirchschlager, R., Springholz, G., Chen, Z., Debnath, M., Oka, Y., (2004) Phys. Rev. B, 70, p. 035209Heiss, W., Prechtl, G., Springholz, G., (2001) Phys. Rev. B, 63, p. 165323Heiss, W., Prechtl, G., Springholz, G., (2001) Appl. Phys. Lett., 78, p. 3484Krenn, H., Herbst, W., Pascher, H., Ueta, Y., Springholz, G., Bauer, G., (1999) Phys. Rev. B, 60, p. 8117Springholz, G., Schwarzi, T., Aigle, M., Pascher, H., Heiss, W., (2000) Appl. Phys. Lett., 76, p. 1807Nolting, W., Mathi Jaya, S., Rex, S., (1996) Phys. Rev. B, 54, p. 14455Umehara, M., (2003) Phys. Rev. B, 68, p. 19320
Femtosecond phononic coupling to both spins and charges in a room-temperature antiferromagnetic semiconductor
No full textSpintronics is postulated on the possibility to employ the magnetic degree of freedom of electrons for computation and couple it to charges. In this view the combination of the high frequency of spin manipulations offered
by antiferromagnets, with the wide tunability of the electronic properties peculiar of semiconductors, provides
a promising and intriguing platform. Here we explore this scenario in α-MnTe, which is a semiconductor
antiferromagnetically ordered at room temperature. Relying on a Raman mechanism and femtosecond laser
pulses, we drive degenerate modes of coherent optical phonons, which modulate the chemical bonds involved
in the superexchange interaction. The spectrally resolved measurements of the transient reflectivity reveal a
coherent modulation of the band gap at the frequency of 5.3 THz. The detection of the rotation of the polarization,
typically associated with magneto-optical effects, shows coherent and incoherent contributions. Modeling how
the ionic motion induced by the phonons affects the exchange interaction in the material, we calculate the
photoinduced THz spin dynamics: the results predict both a coherent and incoherent response, the latter of which
is consistent with the experimental observation. Our work demonstrates that the same phonon modes modulate
both the charge and magnetic degree of freedom, suggesting the resonant pumping of phonons as a viable way
to link spin and charge dynamics even in nonlinear regimes
Observation of large-scale surface undulations due to inhomogeneous dislocation strain fields in lattice-mismatched epitaxial layers
No full textStrain contrast in scanning tunneling microscopy imaging of subsurface dislocations in lattice-mismatched heteroepitaxy
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Study of misfit-dislocation formation in strained-layer heteroepitaxy using ultrahigh vacuum scanning tunneling microscopy
No full textTe molecular beam epitaxy by reflection high-energy electron diffraction intensity oscillations
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