Theoretical study of anomalous liquid states in low-dimensional fermion systems

低维费米子系统反常液态的理论研究

• 批准号: 10203206
• 负责人: OGATA Masao
• 金额: $ 2.82万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research on Priority Areas (B)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10203206/
• 关键词: one-dimensional fermion systems; Tomonaga-Luttinger liquid; spin gap; charge density wave; frustration; 低次元; 液体ヘリウム

In the fermion systems in low-dimensiorial geometries, it is believed that an anomalous state called as Tomonaga-Luttinger liquid is realized. We have studied several issues about its properties and obtained some new results as follows.1) In the case where there is an excitation gap for the spin degrees of freedom, we have studied the behaviors of spectrum of Green's functions, spin response functions and charge response functions. We have found characteristic correlation exponents which are different from the conventional ones.2) We have developed perturbative calculations for the quasi-one-dimensional model and found a crossover from purely one-dimensional behavior to two-dimensional behaviors.3) We have studied the mechanism and temperature dependence of the coexistence of charge density wave and spin density wave. Especially using a renormalization group technique, we found that there are two possible coexistent states and a crossover occurs as a function of temperature.4) Considering the spin-charge separation, we studied variationally the ground states of two-layered one-dimensional fermion systems. There are several interesting magnetic states depending on the density in the second layer. A frustration-induced melting of the charge density wave has been also investigated.5) We have studied the possibilities of stripe states where charges are localized in one-dimensional stripes and the system is decomposed into localized spin region and one-dimensional charge liquid.6) Using a model in which there is a short-range repulsion between one-dimensional bosons, we have studied the Green's function and clarified the difference from the fermion systems

在低维几何的费米子系统中，一般认为存在一种称为Tomonaga-Luttinger液体的反常态。我们对它的性质进行了研究，得到了以下一些新的结果：1）在自旋自由度存在激发能隙的情况下，研究了绿色函数、自旋响应函数和电荷响应函数的谱行为。我们发现了与传统相关指数不同的特征相关指数。2）我们对准一维模型进行了微扰计算，发现了从纯一维行为到二维行为的交叉。3）我们研究了电荷密度波和自旋密度波共存的机制和温度依赖性。特别是利用重正化群技术，我们发现存在两种可能的共存态，并且随着温度的变化会出现交叉。4）考虑自旋-电荷分离，我们变分研究了双层一维费米子系统的基态。有几个有趣的磁性状态取决于第二层中的密度。5）我们研究了在一维条纹中局域电荷的条纹态的可能性，并将系统分解为局域自旋区和一维荷电液体。6）利用一维玻色子之间存在短程排斥的模型，我们研究了绿色函数，阐明了它与费米子系统的区别

项目成果

H.Yamase, H.Kohno, H.Fukuyama, M.Ogata: "Effects of Charge Density Modulation on Incommensurate Antiferromagnetism:Ginzburg-Landau Study"J.Phys.Soc.Japan. 68. 1082-1085 (1999)

H.Yamase、H.Kohno、H.Fukuyama、M.Ogata：“电荷密度调制对不相称反铁磁性的影响：Ginzburg-Landau 研究”J.Phys.Soc.Japan。

N.Kobayashi, M.Ogata, K.Yonemitsu: "Coexistence of SDW and Purely-Electronic CDW in Quarter-Filled Organic Conductors"J.Phys.Soc.Japan. 67. 1198-1101 (1998)

N.Kobayashi、M.Ogata、K.Yonemitsu：“四分之一填充有机导体中 SDW 和纯电子 CDW 的共存”J.Phys.Soc.Japan。

M.Ogata: "Stripe States in the Two-Dimensional t-J Model"J.Phys.Soc.Jpn.Supple. 69. 22-25 (2000)

M.Ogata：“二维 t-J 模型中的条纹状态”J.Phys.Soc.Jpn.Supple。

M.Ogata, N.Kobayashi, K.Yonemitsu: "Coexistence of SDW and purely-electronic CDW in quarter-filled organic conductors"Synth.Metals. 103. 2242-2243 (1999)

M.Ogata、N.Kobayashi、K.Yonemitsu：“SDW 和纯电子 CDW 在四分之一填充有机导体中的共存”Synth.Metals。

M. Ishihara: "Spectral functions of one-dimensional Electron systems with Ising-like spin gap"J. Phys. Soc. Jpn.. 68. 350-353 (1999)

M. Ishihara：“具有类伊辛自旋间隙的一维电子系统的谱函数”J。