Mahmoudian Samiyeh, Rademaker Louk, Ralko Arnaud, Fratini Simone, Dobrosavljević Vladimir
Department of Physics and National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32306, USA.
Kavli Institute for Theoretical Physics, University of California Santa Barbara, Santa Barbara, California 93106, USA.
Phys Rev Lett. 2015 Jul 10;115(2):025701. doi: 10.1103/PhysRevLett.115.025701. Epub 2015 Jul 8.
We show that introducing long-range Coulomb interactions immediately lifts the massive ground state degeneracy induced by geometric frustration for electrons on quarter-filled triangular lattices in the classical limit. Important consequences include the stabilization of a stripe-ordered crystalline (global) ground state, but also the emergence of very many low-lying metastable states with amorphous "stripe-glass" spatial structures. Melting of the stripe order thus leads to a frustrated Coulomb liquid at intermediate temperatures, showing remarkably slow (viscous) dynamics, with very long relaxation times growing in Arrhenius fashion upon cooling, as typical of strong glass formers. On shorter time scales, the system falls out of equilibrium and displays the aging phenomena characteristic of supercooled liquids above the glass transition. Our results show remarkable similarity with the recent observations of charge-glass behavior in ultraclean triangular organic materials of the θ-(BEDT-TTF)(2) family.
我们表明，在经典极限下，引入长程库仑相互作用会立即消除四分之一填充三角晶格上电子因几何阻挫而导致的大量基态简并。重要的结果包括稳定条纹有序的晶体（全局）基态，同时还会出现许多具有非晶“条纹玻璃”空间结构的低能亚稳态。因此，条纹序的熔化在中间温度下会导致一种阻挫库仑液体，其动力学表现出显著的缓慢（粘性）特性，随着冷却，非常长的弛豫时间以阿仑尼乌斯方式增长，这是强玻璃形成体的典型特征。在更短的时间尺度上，系统会偏离平衡态，并表现出玻璃化转变温度以上过冷液体特有的老化现象。我们的结果与最近在θ-（BEDT-TTF）₂家族的超清洁三角有机材料中观察到的电荷玻璃行为有显著相似性。
