Evidence of Novel Quasiparticles in a Strongly Interacting Two-Dimensional Electron System: Giant Thermopower and Metallic Behaviour
Evidence of Novel Quasiparticles in a Strongly Interacting Two-Dimensional Electron System: Giant Thermopower and Metallic Behaviour
复制标题
强相互作用二维电子系统中新型准粒子的证据：巨热电和金属行为
DOI：
10.1007/s10909-012-0718-0
复制
发表时间：
2012
影响因子：
2
通讯作者：
A. Ghosh
中科院分区：
文献类型：
--
作者：
V. Narayan;M. Pepper;J. Griffths;H. Beere;F. Sfigakis;G. Jones;D. Ritchie;A. Ghosh
我们报告了亚开尔文温度下 GaAs/AlGaAs 异质结构中低密度 (1014 m−2) 介观二维电子系统 (2DES) 的热电势 (S) 和电阻率 (ρ2DES) 测量。我们观察到在温度 ≲0.7 K 时，S 作为温度的函数线性增长，表明金属行为。有趣的是，这种金属性并不像德鲁德那样，表现出几个不寻常的特征：(i) S 的大小超出了莫特预测，该预测对于相似载流子密度下的非相互作用金属 2DES 有效，超过两个数量级； (ii) 此状态下的 ρ2DES 比电阻量 h/e2 大两个数量级，并且表现出很小的温度依赖性。我们提供的证据表明，这些观察结果是由于 2DES 中非电子类的新型准粒子的形成而产生的。最后，ρ2DES 和 S 在密度依赖性方面表现出有趣的解耦，后者表现出惊人的振荡，甚至电阻率中完全不存在的符号变化。
We report thermopower (S) and electrical resistivity (ρ2DES) measurements in low-density (1014 m−2), mesoscopic two-dimensional electron systems (2DESs) in GaAs/AlGaAs heterostructures at sub-Kelvin temperatures. We observe at temperatures ≲0.7 K a linearly growing S as a function of temperature indicating metal-like behaviour. Interestingly this metallicity is not Drude-like, showing several unusual characteristics: (i) the magnitude of S exceeds the Mott prediction valid for non-interacting metallic 2DESs at similar carrier densities by over two orders of magnitude; and (ii) ρ2DES in this regime is two orders of magnitude greater than the quantum of resistance h/e2 and shows very little temperature-dependence. We provide evidence suggesting that these observations arise due to the formation of novel quasiparticles in the 2DES that are not electron-like. Finally, ρ2DES and S show an intriguing decoupling in their density-dependence, the latter showing striking oscillations and even sign changes that are completely absent in the resistivity.
局域二维电子系统中磁场引起的不稳定性
影响因子：
3.7
作者：
Baenninger M
通讯作者：
Baenninger M