Temperature dependence of the resistivity in Mn-doped samples [top panel (a)], the plots of vs [middle panel (b)], and vs [bottom panel (c)]. The lines in the top panel are to guide the eyes while those in the middle and bottom panels are the linear fits of the data.
vs for five Mn-doped samples with different parameters and . The solid line is the function given by Eq. (11).
The plots of vs and in Mn-doped samples. The solid line is to guide the eyes. The dashed and dotted lines are the linear fit of the data.
The plots of vs for Mn-doped (crosses, this work), Cr-doped (open triangles, the data are taken from Ref. 16), and Co-doped (closed circles, the data are taken from Ref. 17) samples of . The lines are to guide the eyes.
The doping levels, the values of the characteristic temperatures ( and ) and of the onset temperatures( and ), and the prefactor parameters ( and ) of the Mott- and the SE-VRH conductivity regimes, respectively.
The widths of the impurity band and of the soft Coulomb gap , the critical crossover temperatures in the models of Rosenbaum and Shlimak et al. , the scaling constant and temperature , the ratio of of the DOS parameters in the Mott- and the SE-VRH conduction models, and the rigid gap .
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