Dynamical density and spin response functions of two-dimensional correlated fermion systems: Self-consistent second-order perturbation theory
Dynamical density and spin response functions of two-dimensional correlated fermion systems: Self-consistent second-order perturbation theory
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二维相关费米子系统的动力密度和自旋响应函数：自洽二阶微扰理论
DOI：
10.1103/physrevb.88.014529
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发表时间：
2013
影响因子：
3.7
通讯作者：
A. Kotani and D. S. Hirashima
中科院分区：
文献类型：
--
作者：
T. Mito;T. Koyama;K. Nakagawara;T. Ishida;K. Ueda;T. Kohara;他8名;天谷直樹，奥雄太，山口博則，小野俊雄，松尾晶，金道浩一，野尻浩之，細越裕子;A. Kotani and D. S. Hirashima
利用模型哈密顿量，用自洽二阶微扰理论研究了二维费米子系统的动力学密度和自旋响应。特别注意了在大波矢下的密度响应，其中报道了在二维液氦中粒子-空穴连续体下面发展出一个尖峰模式。我们发现，在较大的波矢下，随着相互作用的开始，动力学密度结构因子中的一个峰值向较低的能量方向移动，但由于准粒子的强烈阻尼效应，它并不够尖锐，不足以表示一个明确的模式。我们指出，在解释二维液体中的传播模时，有必要适当地处理大阻尼效应。
Dynamical density and spin responses of a two-dimensional fermion system are studied with the self-consistent second-order perturbation theory using a model Hamiltonian. Special attention is paid to the density response at a large wave vector, where it was reported that a sharp mode develops below the particle-hole continuum in two-dimensional liquidHe. We find that at a large wave vector, a peak in the dynamical density structure factor shifts to lower energy as interaction sets in, but it is not sharp enough to represent a well-defined mode because of the strong damping effect of the quasiparticles. We point out that it is necessary to treat the large damping effect properly in explaining the propagating mode found in two-dimensional liquidHe.