Resistivity saturation in a weakly interacting two-dimensional Fermi liquid at intermediate temperatures

We report an unusual temperature dependence in the magnetoresistance of a weakly interacting high mobility 2D electron gas (2DEG) under a parallel magnetic field and in the current configuration $\mathit{I}\perp \mathit{B}$. While the linear temperature dependence below 10 K and the exponential temperature dependence above 40 K agree with the existing theory of electron-phonon scattering, a field-induced resistivity saturation behavior characterized by an almost complete suppression of the temperature dependence is observed from approximately 20 to 40 K, which is in sharp contrast to the phenomenology observed in the configuration $\mathit{I}\parallel \mathit{B}$. Possible origins of this intermediate temperature phenomenon are discussed.

Figure 1

Examples of longitudinal resistance $R_{xx}$ as a function of field at several temperatures in the configuration $\mathit{I}\perp \mathit{B}$. Inset: The normalized resistance as a function of field at several temperatures (matching those in the main panel) in the configuration $\mathit{I}\perp \mathit{B}$.

Figure 2

(a) Longitudinal resistance $R_{xx}(B,T)$ and (b) normalized resistance from 0 to 10.5 T in the configuration $\mathit{I}\perp \mathit{B}$. (c) Longitudinal resistance $R_{xx}(B,T)$ and (d) normalized resistance from 11.5 to 45 T in the configuration $\mathit{I}\perp \mathit{B}$. In both the low- and high-temperature limits the qualitative temperature dependence remains qualitatively unsuppressed by the applied magnetic field, but in the intermediate region a resistivity saturation is observed.

Figure 3

(a) The resistance anisotropy data at 0 T (black square), 9 T with $\mathit{I}\parallel \mathit{B}$ (red circle), and 9 T with $\mathit{I}\perp \mathit{B}$ (blue square), extracted from the temperature sweep data at fixed fields. The resistivity saturation effect is only apparent when $\mathit{I}\perp \mathit{B}$. (b) The resistance anisotropy data at 15 T with $\mathit{I}\parallel \mathit{B}$ (red circles) and 15 T with $\mathit{I}\perp \mathit{B}$ (blue square), extracted from the field sweep data at fixed temperatures. The 0-T and the 9-T $\mathit{I}\parallel \mathit{B}$ data can be fit to Eq. (1) with $a_1=0\Omega$, $a_2=2.57\Omega$ K, $b_1=3.45\times {10}^6\Omega$ K, and $b_2=453$ K (black solid line) and $a_1=66.82\Omega$, $a_2=2.92\Omega$ K, $b_1=3.45\times {10}^6\Omega$ K, and $b_2=453$ K (red solid line). The others (9-T $\mathit{I}\perp \mathit{B}$ data, 15-T $\mathit{I}\perp \mathit{B}$ data, and 15-T $\mathit{I}\parallel \mathit{B}$ data) cannot be fit to this functional form, and the dashed lines are guides to the eye.