Theoretical study of anomalous electronic states of vanadium oxides with pyroclore lattice structures

烧绿石晶格结构钒氧化物反常电子态的理论研究

• 批准号: 14540324
• 负责人: OHTA Yukinori
• 金额: $ 1.47万
• 依托单位: Chiba University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14540324/
• 关键词: strongly correlated electron systems; transition metal oxides; DMRG; spin-triplet superconductivity; orbital ordering; charge ordering; frustration; Hubbard model; 超伝導; 金属絶縁体転移; 擬1次元電子系; 電荷ゆらぎ; 量子モンテカルロ; 準1次元系

We have made theoretical and computational studies of strongly correlated electron systems, aiming in particular at elucidation of the mechanisms of the anomalous electronic properties of transition-metal oxides and molecular conductors. We have used the density-matrix renormalization group(DMRG) method for calculating the electronic states of pseudo-one-dimensional models in high accuracy. The main results obtained are the following.1.We have clarified the mechanism of the charge and orbital ordering of the triangular-lattice Hollandite compound Bi_xV_8O_<16>.2.We have clarified the mechanism of the orbital ordering and spin-singlet formation in pyroxene compound NaTiSi_2O_6.3.We have clarified the nature of the anomalous spin excitations that appear in the states of large charge fluctuation.4.We have elucidated the anomalous charge dynamics in the CuO double-chain systems.5.We have proposed the novel mechanism of formation of the spin-gap liquid state that appears when the quantum melting of charge-ordered state occurs in the CuO double-chain systems.6.We have calculated the precise electronic phase diagram of the ground state of the one-dimensional extended Hubbard model.7.We have proposed the novel mechanism of the spin-triplet superconductivity that appears in the two-chain zigzag-bond Hubbard model.

我们对强相关电子系统进行了理论和计算研究，特别是旨在阐明过渡金属氧化物和分子导体异常电子性质的机制。本文采用密度矩阵重整化群（DMRG）方法对赝一维模型的电子态进行了高精度计算。主要结果如下：1.阐明了三角晶格Hollandite化合物Bi_xV_8O_2的电荷和轨道有序化机制<16>; 2.阐明了辉石化合物NaTiSi_2O_3的轨道有序化和自旋单重态形成机制6.3.我们阐明了在大电荷涨落态中出现的反常自旋激发的性质提出了CuO双链体系中电荷有序态量子熔化时自旋能隙液态形成的新机制。6.计算了一维扩展Hubbard模型基态的精确电子相图。7.提出了CuO双链体系中电荷有序态量子熔化时自旋能隙液态形成的新机制。三重态超导电性，出现在两链的超导键哈伯德模型。

项目成果

Optical Conductivity in the CuO Double Chains of PrBa_2Cu_4O_8

PrBa_2Cu_4O_8 CuO双链的光学电导率

• 发表时间: 2003
• 期刊: J.Low Temp.Phys. 131
• 作者: Y.Ohta;R.Amasaki;Y.Shibata
• 通讯作者: Y.Shibata

S.Ejima, T.Nakaegawa, Y.Ohta: "Excitations in the Coupled Spin-Pseudospin Model for Quarter-Filled Ladders"Physica B. 328. 105-107 (2003)

S.Ejima、T.Nakaekawa、Y.Ohta：“四分之一填充梯子的耦合自旋-赝自旋模型中的激发”Physica B. 328. 105-107 (2003)

Optical Conductivity in the CuO Double chains of OrBa_2Cu_4O_8

OrBa_2Cu_4O_8 CuO 双链的光学电导率

• 发表时间: 2003
• 期刊: Journal of Low Temperature Physics 131
• 作者: Y.Ohta;R.Amasaki;Y.Shibata
• 通讯作者: Y.Shibata

Y.Ohta, S.Ejima, T.Nakaegawa: "Interplay between Spin and Charge Excitations in the Coupled Spin-Pseudospin Systems"Journal of Low Temperature Physics. 133. No.3-4. 239-243 (2003)

Y.Ohta、S.Ejima、T.Nakaekawa：“耦合自旋-赝自旋系统中自旋和电荷激发之间的相互作用”低温物理学杂志。

R.Amasaki, Y.Shibata, Y.Ohta: "Optical Conductivity in the CuO Double Chains of PrBa_2Cu_4O_8 : Consequences of Charge Fluctuation"Physical Review B. 66. 012502 (2002)

R.Amasaki、Y.Shibata、Y.Ohta：“PrBa_2Cu_4O_8 的 CuO 双链中的光学电导率：电荷波动的后果”物理评论 B.66.012502 (2002)