论文标题
与键障碍的量子磁铁中的差距重新归一化的自洽t-matrix方法
Self-consistent T-matrix approach to gap renormalization in quantum magnets with bond disorder
论文作者
论文摘要
基于与键障碍的三维量子磁体中状态密度（DOS）的分析性t-matrix近似（SCTMA）的分析理论。它在谐振和非谐振散射的情况下成功地描述了DOS，外观受散射长度和杂质之间的平均距离的比率控制。在这些情况下，对准颗粒带隙的校正分别为$ \ propto c^{2/3} $和$ \ propto c $。此外，该理论为间隙内的结合状态产生了半圆形的DOS形式，在两个限制情况下，在频带DOS和半圆被重叠时，在两个限制情况下导致高度非平凡的DOS。讨论了长波长激发。在共鸣状态下，它们的阻尼几乎是恒定的$ \ propto c^{2/3} $，根据Ioffe-Regel标准，这意味着它们的本地化。该理论的适用性通过对旋转二聚体系统的最新实验数据BA $ _ {3-x} $ sr $ _x $ _x $ cr $ _2 $ _2 $ o $ $ _8 $的定量描述进行了说明。
Based on the self-consistent T-matrix approximation (SCTMA), analytical theory of density of states (DOS) in three-dimensional quantum magnets with the bond disorder is proposed. It successfully describes DOS in both cases of resonant and non-resonant scattering which appearance is governed by the ratio of scattering length and the average distance between impurities. Corrections to the quasiparticles band gap in these cases are shown to be $\propto c^{2/3}$ and $\propto c$, respectively. Moreover, the theory yields a semi-circle form of DOS for the bound states inside the gap which results in highly nontrivial DOS in the intermediate parameters region between two limiting cases when the band DOS and the semi-circle are overlapped. Long-wavelength excitations are discussed. In the resonant regime their damping is almost constant $\propto c^{2/3}$, which according to Ioffe-Regel criterion means their localization. Applicability of the theory is illustrated by a quantitative description of the recent experimental data on spin-dimer system Ba$_{3-x}$Sr$_x$Cr$_2$O$_8$.
