Hidden Fermi-liquid Charge Transport in the Antiferromagnetic Phase of the Electron-Doped Cuprate Superconductors

Systematic analysis of the planar resistivity, Hall effect, and cotangent of the Hall angle for the electron-doped cuprates reveals underlying Fermi-liquid behavior even deep in the antiferromagnetic part of the phase diagram. The transport scattering rate exhibits a quadratic temperature dependence, and is nearly independent of doping and compound and carrier type (electrons versus holes), and hence is universal. Our analysis moreover indicates that the material-specific resistivity upturn at low temperatures and low doping has the same origin in both electron- and hole-doped cuprates.

Figure 1

$ab$-plane resistivity of various cuprate materials. (a)–(e) Raw data (blue circles) and fit to Eq. (2b) (red dashed curves). The estimated contributions $A_0-A_{\log }\log (T/1\mathrm{K})$ are shown as black dashed lines. (f)–(j) Semilog plots of the resistivity. The dashed lines indicate the logarithmic contribution. (k)–(o) Differences between the raw data and fits. The horizontal black dashed lines indicate zero difference and are guides to the eye. The black vertical lines indicate the temperatures above which the fits deviate from the data. The gray shaded bands indicate the temperature range in which the underlying quadratic temperature dependence of the planar resistivity breaks down [38, 41]. The Néel temperature ($T_N\approx 165\mathrm{K}$) of NCCO ($x=0.10$) is shown as a green shaded band [4]. The arrows indicate low-temperature deviations from logarithmic behavior in lightly doped LSCO and YBCO. Except for the new NCCO data, which are consistent with prior work [26], the data are adapted from Refs. [36, 38, 40].

Figure 2

Doping dependence of $A_{2\square }$ for (a) electron- and (b) hole-doped materials, as obtained from fits to Eq. (2b). Note that in Ref. [15] $A_{2\square }$ was estimated for the hole-doped cuprates without considering the logarithmic contribution; see also Ref. [41]. The gray lines are guides to the eye and indicate $1/x$ and $1/p$ dependences, respectively. (c) Scaling relation between $A_{\log \square }$ and $A_{0\square }$. Data are adapted from Refs. [7, 15, 24, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40]. The error bars are 1 standard deviation, estimated from fits with various temperature ranges. At low doping, the low-temperature upturn can no longer be well described by a logarithmic contribution (see Fig. 1 and Ref. [41]), and the obtained coefficients thus depend on the fit temperature range and have large error bars.

Figure 3

Resistivity data and fit for NCCO with (a) $x=0.075$ [26] and (b) $x=0.10$ [present work, same data as in Fig. 1]. (c),(d) Resistivity after subtraction of fitted logarithmic contribution. (e),(f) $1/R_H$ adapted from Ref. [44]; the $1/R_H$ data obtained for our NCCO ($x=0.10$) sample (red triangles) agree with the prior work [44]. The black horizontal dashed lines indicate the magnitude of $1/R_H$ estimated from the chemical dopant concentrations $x=0.075$ and 0.10. (d),(g) Cotangent of the Hall angle. The red dashed lines indicate $\cot ({\theta }_H)\propto C_2{T}^2$. As in Fig. 1, the green bands indicate the estimated Néel temperatures [4].

Figure 4

$C_2$ for various single-layer cuprates. LSCO, Hg1201, and Tl2201 results adapted from Ref. [23]. $C_2$ for NCCO is determined both by method 1 (open symbols) and method 2 (solid symbols). See also Ref. [41].