Department of Physics, Indiana University, Bloomington, Indiana 47405, USA.
Phys Rev Lett. 2010 May 7;104(18):186401. doi: 10.1103/PhysRevLett.104.186401. Epub 2010 May 3.
We demonstrate that, in the presence of Coulomb interactions, electrons in graphene behave like a critical system, supporting power law correlations with interaction-dependent exponents. An asymptotic analysis shows that the origin of this behavior lies in particle-hole scattering, for which the Coulomb interaction induces anomalously close approaches. With increasing interaction strength the relevant power law changes from real to complex, leading to an unusual instability characterized by a complex-valued susceptibility in the thermodynamic limit. Measurable quantities, as well as the connection to classical two-dimensional systems, are discussed.
我们证明，在存在库仑相互作用的情况下，石墨烯中的电子表现得像一个临界系统，支持具有与相互作用相关的指数的幂律相关性。渐近分析表明，这种行为的起源在于粒子-空穴散射，其中库仑相互作用导致异常接近。随着相互作用强度的增加，相关的幂律从实数变为复数，导致了一种不寻常的不稳定性，其特征是在热力学极限下具有复数值的磁化率。讨论了可测量的量以及与经典二维系统的联系。
