School of Physics and Wuhan High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China.
Phys Chem Chem Phys. 2011 Jan 7;13(1):328-36. doi: 10.1039/c0cp00185f. Epub 2010 Oct 29.
The zero- and low-temperature behaviors of a quasi-one-dimensional organic polymer proposed as a symmetrical periodic Anderson-like chain model, in which the localized f orbitals hybridize with the conduction orbitals at even sites, are investigated by means of many-body Green's function theory. In the absence of magnetic field, the ground state of the system turns out to be ferrimagnetic. The temperature-induced phase diagrams have been explored, where the competition between the Hubbard repulsion U on the localized f orbital and the hybridization strength V makes an important impact on the transition temperature. In a magnetic field, it is found that a 1/3 magnetization plateau appears and two critical fields indicating the insulator-metal transitions at zero temperature emerge, which are closely related to the energy bands. Furthermore, the single-site entanglement entropy is a good indicator of quantum phase transitions. The temperature-field-induced phase diagram has also been attained, wherein the magnetization plateau state, the gapless phase and the spin polarized state are revealed. The temperature dependence of thermodynamic quantities such as the magnetization, susceptibility and specific heat are calculated to characterize the corresponding phases. It is also found that the up-spin and down-spin hole excitations are responsible for the thermodynamic properties.
采用多体格林函数理论研究了一个拟一维有机聚合物的零温和低温特性，该聚合物被提出作为一个对称的周期性安德森类链模型，其中局域的 f 轨道与偶数位置的传导轨道杂化。在没有磁场的情况下，系统的基态是反铁磁的。研究了温度诱导的相图，其中局域 f 轨道上的 Hubbard 排斥 U 和杂化强度 V 之间的竞争对转变温度有重要影响。在磁场中，发现出现了 1/3 磁化平台，并且出现了两个零温下指示绝缘-金属转变的临界场，这与能带密切相关。此外，单一位点纠缠熵是量子相变的良好指标。还获得了温度-磁场诱导的相图，其中揭示了磁化平台态、无能隙相和自旋极化态。计算了磁化、磁化率和比热等热力学量的温度依赖性，以表征相应的相。还发现上自旋和下自旋空穴激发是热力学性质的原因。
