arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1002.3693cond-mat.str-el
收藏

三维阻挫超锥格点上哈伯德模型的集团动力学平均场研究

Cluster dynamical mean-field study of the Hubbard model on a 3D frustrated hyperkagome lattice

Masafumi Udagawa, Yukitoshi Motome

摘要:

利用动力学平均场理论的团簇推广,研究了几何阻挫超锥格点上的哈伯德模型。计算了关联金属区的比热($C$)和自旋-晶格弛豫时间($T_1$)随温度($T$)的变化关系。$C/T$在$T=T_{p1}$处显示峰值,并以$T->0$形式快速降低。另一方面,$1/T_1T$在比$T_{p1}$更高的温度$T_{p2}$处具有峰,并且在$T_{p2}$以下大幅降低,遵循Korringa定律$1/T_1 propto T$为$T->0$。两个峰值温度都被抑制,并且随着电子相关性的增加,峰值变得更尖锐。这些行为起源于强重整化的能量尺度在这个挫折系统的特殊的电子结构,一个伪的差距一样的功能,范霍夫奇异性,和平带。结果进行了讨论,在hyperkagome材料,钠$_4$铱$_3$ O $_8$的实验数据进行比较。

英文摘要:

We study the Hubbard model on a geometrically-frustrated hyperkagome lattice by a cluster extension of the dynamical mean field theory. We calculate the temperature ($T$) dependences of the specific heat ($C$) and the spin-lattice relaxation time ($T_1$) in correlated metallic region. $C/T$ shows a peak at $T=T_{p1}$ and rapidly decreases as $T->0$. On the other hand, $1/T_1T$ has a peak at a higher temperature $T_{p2}$ than $T_{p1}$, and largely decreases below $T_{p2}$, followed by the Korringa law $1/T_1 propto T$ as $T->0$. Both peak temperatures are suppressed and the peaks become sharper as electron correlation is increased. These behaviors originate from strong renormalization of the energy scales in the peculiar electronic structure in this frustrated system; a pseudo-gap like feature, the van-Hove singularity, and the flat band. The results are discussed in comparison with the experimental data in the hyperkagome material, Na$_4$Ir$_3$O$_8$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑