Laboratoire de Physique et Etude des Matériaux (CNRS/UPMC), Ecole Supérieure de Physique et de Chimie Industrielles, 10 Rue Vauquelin, F-75005 Paris, France.
Science. 2015 Aug 28;349(6251):945-8. doi: 10.1126/science.aaa8655.
Scattering among electrons generates a distinct contribution to electrical resistivity that follows a quadratic temperature (T) dependence. In strongly correlated electron systems, the prefactor A of this T(2) resistivity scales with the magnitude of the electronic specific heat, γ. Here we show that one can change the magnitude of A by four orders of magnitude in metallic strontium titanate (SrTiO3) by tuning the concentration of the carriers and, consequently, the Fermi energy. The T(2) behavior persists in the single-band dilute limit despite the absence of two known mechanisms for T(2) behavior: distinct electron reservoirs and Umklapp processes. The results highlight the absence of a microscopic theory for momentum decay through electron-electron scattering in various Fermi liquids.
电子的散射会导致电导率产生明显的变化，这种变化遵循二次温度（T）依赖关系。在强关联电子系统中，这种 T(2)电阻率的前因子 A 与电子比热 γ 的大小成正比。在这里，我们表明可以通过调节载流子的浓度（从而调节费米能），在金属钛酸锶（SrTiO3）中使 A 的量级发生四个数量级的变化。尽管不存在 T(2)行为的两种已知机制：不同的电子库和厄米克朗过程，但 T(2)行为在单带稀溶液极限中仍然存在。研究结果突出了在各种费米液体中，通过电子-电子散射来衰减动量的微观理论的缺失。
