准一维自旋链与自旋梯子共存Sr14Cu24O41体系电荷有序行为的研究

项目名称： 准一维自旋链与自旋梯子共存Sr14Cu24O41体系电荷有序行为的研究

项目编号： No.11304091

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 胡妮

作者单位： 湖北工业大学

项目金额： 28万元

中文摘要： 自掺杂空穴Sr14Cu24O41体系因同时有准一维自旋链与自旋梯子共存，晶格、自旋、电荷、轨道多种相互作用竞争，导致在链或梯子上出现自旋dimer反铁磁序、Zhang-Rice单态、有能隙自旋液体、电荷密度波（CDW）等多种基态行为，且其高浓度Ca掺杂样品是第一个非正方铜氧化合物超导体。特别是该体系自旋梯子上的低温电荷密度波不同于通常Peierls型CDW，可能的驱动机制是电子间的关联作用，伴随CDW出现的是绝缘体-绝缘体相变，形成CDW的载流子是带正电的空穴。本课题将通过与单一自旋链、单一自旋梯子系统的比较研究、利用不等价和等价掺杂改变载流子浓度，系统考察这类新型CDW电荷有序形成机理、相变过程，CDW本征性质以及对外场的响应行为。这不仅将有助于人们加深对Sr14Cu24O41体系各种相互作用和基态性质的认识，而且也将丰富人们对铜氧化物超导系统，以及对整个CDW电荷有序行为的整体认识。

中文关键词： 电荷有序；自旋梯子；自旋链；多铁性；

英文摘要： Self-doping compound Sr14Cu24O41 is coexisted by quasi-one-dimensional spin-chain and spin-ladder, the competition among lattice, spin, charge, and orbital degree of freedoms gives rise fantastic physical properties including spin-dimer antiferromagnetic ordering, Zhang-Rice singlet, gapped spin liquid, charge density wave, and superconductor. The high level Ca-doping compound is the first non-cubic cuprate superconductor. Interestingly, the low temperature charge-density-wave, composed of positive holes, in the spin-ladder is different from the typical Peierls-type charge-density-wave, which is possibly caused by the electron correlation and accompanied by insulator-insulator phase transition. For current proposal, we are intending to choose typical single spin-chain or spin-ladder compounds to comprehensively investigate the physics of charge-density-wave, and phase transition via kinds of doping. The target of current proposal is to deeply understand the diverse correlation and ground state of Sr14Cu24O41, to enrich the physics of cuprate superconductors and charge-density-wave systems.

英文关键词： the charge ordering；spin ladder；spin chain；multiferroicity；