"Interlayer magnetoresistance in strongly anisotropic quasi-2D compounds"
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The angular and field dependence of magnetoresistance (MR) is a very powerful
tool to determine the details of electronic spectrum and of Fermi-surface
geometry of various compounds, which is crucial for understanding their
electronic properties. Recently, the magnetic quantum oscillations (MQO) and
angular magnetoresistance oscillations were applied to extract the Fermi-surface
geometry and the electron dispersion in cuprate and pnictide high-temperature
superconductors. Both these effects are traditionally used to study the electron
dispersion in layered organic metals and most other metallic compounds. As the
anisotropy of the compounds increases, the standard 3D theory of
magnetoresistance becomes inapplicable, and a new theoretical description is
required.
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The theory of magnetoresistance is developed in the “weakly incoherent” limit,
when the electron interlayer tunneling conserves the in-plane momentum, but the
time of this tunneling is much longer than mean scattering time by impurities
and/or cyclotron period [1-3]. This theory predicts several new qualitative
features. First, the nonoscillating part of interlayer magnetoresistance
increases as a square root of interlayer component of magnetic field. This
contradicts the standard theory of magnetoresistance, which states that only a
perpendicular-to-current component of magnetic field affects this current. The
magnetic quantum oscillations are stronger damped in this limit and the angular
dependence of magnetoresistance changes compared to the predictions of the
standard theory. These new features in magnetoresistance appear because the
effect of impurity scattering is enhanced by low-dimensionality, naturally
appearing in layered conductors. The experiments on magnetoresistance in layered
organic metal have been performed to check the predictions of the new theory.
The agreement turned out to be very nice, especially for clean samples.[4] In
strongly anisotropic compounds with low electron concentration a magnetic field
may lead to even steeper field-dependence of interlayer magnetoresistance
because of the Coulomb anomaly.[5,6]
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*References*
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1. P. D. Grigoriev, Phys. Rev. B *83*, 245129 (2011).
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2. P. D. Grigoriev, JETP Letters *94*, 47 (2011).
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3. P.D. Grigoriev, Fizika Nizkikh Temperatur, *37* (9-10), 930 (2011).
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4. P. D. Grigoriev, M. V. Kartsovnik, W. Biberacher, Phys. Rev. B *86*, 165125
(2012).
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5. P. D. Grigoriev, Physica B *407*, 1932 (2012); ArXiv: cond-mat/1111.2432
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6. P. D. Grigoriev, to be published.