Metal-Insulator Transitions
Investigations of charge dynamics at the metal-insulator transitions provide important information about the physical mechanism of this phenomena. One of the open problems in this field is to follow the transformation of the response of localized carriers (Lorentzian-like) to the Drude-response of the free carriers in the metallic state.
Broadband conductivity of magnetite at the Verwey transition3
Frequency dependence of the conductivity and the dielectric constant of magnetite above and below TV = 123 K. Symbols below 40 cm-1 and solid lines above 30 cm-1 represent the experimental data, dashed lines - model calculations. The main contribution to the model calculations is given by the hopping term below TV and a Drude-conductivity above TV. |
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Scaling of conductivity and dielectric constant at the metal-insulator transition
Dielectric permittivity of La1-xSrxMnO3 plotted as function of conductivity with the temperature as tuning parameter and for B = 0. The dashed line indicates a linear scaling between permittivity and conductivity with the characteristic frequency of 6 THz. |
Selected publications
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A. Pimenov, M. Biberacher, D. Ivannikov, A. Loidl, A. A. Mukhin, Yu. G. Goncharov, and A. M. Balbashov
Scaling of terahertz conductivity at the metal-insulator transition in doped manganites
Phys.Rev. B 73, 220407(R) (2006)
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A. Pimenov, S. Tachos, T. Rudolf, A. Loidl, D. Schrupp, R. Claessen, and V. A. M. Brabers
Terahertz Conductivity at the Verwey Transition in Magnetite
Phys.Rev. B, 72, 035131 (2005) -
N. N. Kovaleva, A. V. Boris, C. Bernhard, A. Kulakov, A. Pimenov, A. M. Balbashov, G. Khaliullin, and B. Keimer
Spin-Controlled Mott-Hubbard Bands in LaMnO3 Probed by Optical Ellipsometry
Phys.Rev. Lett. 93, 147204 (2004) -
J. Sichelschmidt, M. Paraskevopoulos, M. Brando, R. Wehn, D. Ivannikov, F. Mayr, K. Pucher, J. Hemberger, A. Pimenov, H.-A. Krug von Nidda, P. Lunkenheimer, V. Yu. Ivanov, A. A. Mukhin, A. M. Balbashov and A. Loidl
Magnetic, electronic, dielectric and optical properties of Pr(Ca:Sr)MnO3
Eur. Phys. J. B 20, 7 (2001)
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A. Pimenov, Ch. Hartinger, A. Loidl, A. A. Mukhin, V. Yu. Ivanov, and A. M. Balbashov
Itinerant versus localized transport in La1-xSrxMnO3 for x<=0.175
Phys. Rev. B 59, 12419 (1999)