Low-temperature asymptotics for the transverse dynamical structure factor for a magnetically polarized $XX$ chain at small and negative frequencies

Low-temperature asymptotics for transverse autocorrelator of the magnetically polarized Ising chain studied by ordinary and nested Dyson equations

Suggesting two versions for the Plakida-Tserkovnikov algorithm breakdown in the low-temperature regime, we derive ordinary and nested Dyson equations for the transverse autocorrelator of the magnetically polarized Ising chain. Using them we get the corresponding low-temperature asymptotics for the autocorrelator. We show that the ordinary Dyson equation results in a correct $o({\rm e}^{-βE_{gap}})$ account of the magnon creation process, while the nested Dyson equation additionally gives the correct $o({\rm e}^{-βE_{gap}})$ contribution associated with transitions from magnons to bound two-mag…

Low-temperature asymptotic of the transverse dynamical structure factor for a magnetically polarized XX chain

Dyson equation for the real two-time commutator retarded one-magnon Green function of the ferromagnetically polarized XX chain is suggested following the Plakida-Tserkovnikov algorithm. Starting from this result a low-temperature integral representation for the corresponding magnon self energy is obtained by the truncated form factor expansion however without any resummations. Within the suggested approach the low-temperature asymptotics of the transverse dynamical structure factor may be readily studied. Some obtained line shapes are presented.

掺杂过渡金属氧化物中轨道极化相和磁有序相的相互作用

Interplay of orbitally polarized and magnetically ordered phases in doped transition metal oxides

在平均场近似下，我们研究了空穴掺杂时电子相互作用的二维模型的磁不稳定性。特别是，我们解决的轨道极化状态的发生，由于不等价的轨道，以及它们与铁磁和反铁磁自旋顺序的相互作用。详细讨论了Hund交换耦合J_H和晶场轨道分裂E_z在稳定竞争相中所起的作用。

低温下磁极化易轴$XXZ$链的横向动力学结构因子中的磁振子峰线型

Magnon peak lineshape in the transverse dynamical structure factor of a magnetically polarized easy-axis $XXZ$ chain at low temperatures

本文研究了低温下铁磁极化带隙XXZ自旋链，利用Dyson方程推导出磁振子峰线型的低温公式，并分析了易轴链中能量分离条件下的线型特征及共振偏移行为。

石墨烯中磁性杂质诱导的自旋极化半导体

Spin-Polarized Semiconductor Induced by Magnetic Impurities in Graphene

吸附在石墨烯上的磁性杂质通过巡游电子进行磁耦合。这种相互作用在石墨烯的能带结构中打开了间隙。结果很大程度上取决于磁性杂质的分布。虽然随机掺杂产生半导体，但如果所有或大多数杂质位于同一子晶格中，则自旋简并被去除，并且出现自旋极化半导体。

Magnetically induced Ferroelectricity in Bi$_2$CuO$_4$

The tetragonal copper oxide Bi$_2$CuO$_4$ has an unusual crystal structure with a three-dimensional network of well separated CuO$_4$ plaquettes. This material was recently predicted to host electronic excitations with an unconventional spectrum and the spin structure of its magnetically ordered state appearing at T$_N$ $\sim$43 K remains controversial. Here we present the results of detailed studies of specific heat, magnetic and dielectric properties of Bi$_2$CuO$_4$ single crystals grown by the floating zone technique, combined with the polarized neutron scattering and high-resolution X-ray…