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4 results for au:Andreev_V in:cond-mat

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Nonlinear Hysteretic Torsional Waves
J. Cabaret, P. Béquin, G. Theocharis, V. Andreev, V.E. Gusev, V. Tournat
Jan 12 2015 physics.class-ph cond-mat.soft arXiv:1501.02179v1

@misc{1501.02179, author = {J.~Cabaret and P.~Béquin and G.~Theocharis and V.~Andreev and V.E.~Gusev and V.~Tournat}, title = {{N}onlinear {H}ysteretic {T}orsional {W}aves}, year = {2015}, eprint = {1501.02179}, note = {arXiv:1501.02179v1} }
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We theoretically study and experimentally report the propagation of nonlinear hysteretic torsional pulses in a vertical granular chain made of cm-scale, self-hanged magnetic beads. As predicted by contact mechanics, the torsional coupling between two beads is found nonlinear hysteretic. This results in a nonlinear pulse distortion essentially different from the distortion predicted by classical nonlinearities, and in a complex dynamic response depending on the history of the wave particle angular velocity. Both are consistent with the predictions of purely hysteretic nonlinear elasticity and the Preisach-Mayergoyz hysteresis model, providing the opportunity to study the phenomenon of nonlinear dynamic hysteresis in the absence of other type of material nonlinearities. The proposed configuration reveals a plethora of interesting phenomena including giant amplitude-dependent attenuation, short term memory as well as dispersive properties. Thus, it could find interesting applications in nonlinear wave control devices such as strong amplitude-dependent filters.
Optical conductivity of V4O7 across its metal-insulator transition
I. Lo Vecchio, M. Autore, F. D'Apuzzo, F. Giorgianni, A. Perucchi, U. Schade, V. N. Andreev, V. A. Klimov, S. Lupi
Jul 07 2014 cond-mat.str-el arXiv:1407.1081v1

@misc{1407.1081, author = {I.~Lo Vecchio and M.~Autore and F.~D'Apuzzo and F.~Giorgianni and A.~Perucchi and U.~Schade and V.~N.~Andreev and V.~A.~Klimov and S.~Lupi}, title = {{O}ptical conductivity of {V}4{O}7 across its metal-insulator transition}, year = {2014}, eprint = {1407.1081}, note = {arXiv:1407.1081v1} }
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The optical properties of a V4O7 single crystal have been investigated from the high temperature metallic phase down to the low temperature antiferromagnetic insulating one. The temperature dependent behavior of the optical conductivity across the metal-insulator transition (MIT) can be explained in a polaronic scenario. Charge carriers form strongly localized polarons in the insulating phase as suggested by a far-infrared charge gap abruptly opening at T_MIT = 237 K. In the metallic phase instead the presence of a Drude term is indicative of fairly delocalized charges with a moderately renormalized mass m* = 5m_e. The electronic spectral weight is almost recovered on an energy scale of 1 eV, which is much narrower compared to VO2 and V2O3 cases. Those findings suggest that electron-lattice interaction rather than electronic correlation is the driving force for V4O7 metal-insulator transition.
Phonon Resonators : The Building Blocks of Nanocomposite Adjusting the Electron - Phonon Interaction
V.G. Andreev, L.V. Kravchuk, S.G. Lebedev
Dec 21 2010 cond-mat.supr-con arXiv:1012.4286v1

@misc{1012.4286, author = {V.G.~Andreev and L.V.~Kravchuk and S.G.~Lebedev}, title = {{P}honon {R}esonators : {T}he {B}uilding {B}locks of {N}anocomposite {A}djusting the {E}lectron - {P}honon {I}nteraction}, year = {2010}, eprint = {1012.4286}, note = {arXiv:1012.4286v1} }
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The nanocrystallite have the finite number of the oscillation modes. Their number increases proportionally to a cube of the characteristic size. Thus the oscillation spectrum of nanocrystal becomes discrete, and the separate modes of oscillations does not interact with each other, that considerably strengthens all phonon modulated processes in a crystal. Covering of such a nanocrystallite with the shielding surface of a material with the higher nuclear weight will allow to create the phonon resonators whose oscillation modes will represent the standing waves and, will be amplified by the resonant manner. The composites made of phonon resonators will allow to produce a perspective functional material for the electronics with adjustable structure and properties. Some new mechanism of HTS based on phonon resonators is proposed.
Phonon Resonant Cavities as a Promising Building Blocks of Hand-Made Nanocrystalline Matter
V. G. Andreev, L. V. Kravchuk, S. G. Lebedev, A. V. Samokhin, N. V. Alekseev
Dec 24 2007 cond-mat.supr-con cond-mat.soft arXiv:0712.3680v1

@misc{0712.3680, author = {V.~G.~Andreev and L.~V.~Kravchuk and S.~G.~Lebedev and A.~V.~Samokhin and N.~V.~Alekseev}, title = {{P}honon {R}esonant {C}avities as a {P}romising {B}uilding {B}locks of {H}and-{M}ade {N}anocrystalline {M}atter}, year = {2007}, eprint = {0712.3680}, note = {arXiv:0712.3680v1} }
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The nanocrystallite have the finite number of the oscillation modes. Their number increases proportionally to a cube of the characteristic size. Thus the oscillation spectrum of nanocrystal becomes discrete, and the separate modes of oscillations does not interact with each other, that considerably strengthens all phonon modulated processes in a crystal. Covering of such a nanocrystallite with the shielding surface of a material with the higher nuclear weight will allow to create the phonon resonant cavity whose oscillation modes will represent the standing waves and, will be amplified by the resonant manner. The composites made of phonon resonant cavities will allow to produce a perspective functional material for the electronics with adjustable structure and properties.