论文标题
Luttinger定理和粒子孔对称性的精确实验测试,用于强烈相关的费米子系统
Precise Experimental Test of the Luttinger Theorem and Particle-Hole Symmetry for a Strongly Correlated Fermionic System
论文作者
论文摘要
物理学中的一个基本概念是费米表面,这是动量空间中恒定能量表面,该表面包含所有被占用的量子状态在绝对零温度下。 1960年,Luttinger假定即使在电子 - 电子相互作用开启的情况下,也应不受影响,只要相互作用不引起相变。了解什么决定费米表面尺寸是一个至关重要但未解决的问题,例如高$ t_ {c} $超导体。在这里,我们为二维费米液体系统提供了Luttinger定理的精确测试,其中奇异的准颗粒本身从强烈的相互作用中出现,即复合材料费米斯(CFS)的羊毛植物。通过直接,CFS的Fermi波向量的几何共振测量至非常低的电子密度,我们表明Luttinger Therorem在相互作用的强度范围内被遵守,因为Fermi Sea Sea面积是由低矮的陆地上的\ textit {MinortiT {MINSTIT {少数族裔载体的密度}确定的。我们的数据还解决了有关CFS是否遵守粒子孔对称性以及是否是狄拉克粒子的持续争论。我们发现遵守颗粒 - 孔对称性,但是所测量的费米海域与CFS的狄拉克模型的预测有定量不同。
A fundamental concept in physics is the Fermi surface, the constant-energy surface in momentum space encompassing all the occupied quantum states at absolute zero temperature. In 1960, Luttinger postulated that the area enclosed by the Fermi surface should remain unaffected even when electron-electron interaction is turned on, so long as the interaction does not cause a phase transition. Understanding what determines the Fermi surface size is a crucial and yet unsolved problem in strongly interacting systems such as high-$T_{c}$ superconductors. Here we present a precise test of the Luttinger theorem for a two-dimensional Fermi liquid system where the exotic quasi-particles themselves emerge from the strong interaction, namely for the Fermi sea of composite fermions (CFs). Via direct, geometric resonance measurements of the CFs' Fermi wavevector down to very low electron densities, we show that the Luttinger theorem is obeyed over a significant range of interaction strengths, in the sense that the Fermi sea area is determined by the density of the \textit{minority carriers} in the lowest Landau level. Our data also address the ongoing debates on whether or not CFs obey particle-hole symmetry, and if they are Dirac particles. We find that particle-hole symmetry is obeyed, but the measured Fermi sea area differs quantitatively from that predicted by the Dirac model for CFs.