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arXiv 1703.08142cond-mat.str-el
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二维t-J模型的极端相关费米液体理论:低能性质

Extremely Correlated Fermi Liquid theory of the $t$-$J$ model in 2 dimensions: Low Energy properties

University of California, Santa Cruz(加州大学圣克鲁兹分校)

B. Sriram Shastry, Peizhi Mai

AI总结:

本研究基于二维t-J模型,通过极端相关费米液体理论分析低能性质,揭示了电子掺杂与空穴掺杂在电阻率曲率上的差异。

摘要:

二维tJ模型金属态的低能性质在不同密度和温度下被呈现,考虑了次近邻跃迁t'的符号,正负号分别对应空穴或电子掺杂。计算采用从极端相关费米液体理论中获得的格林函数闭合方程集。这些方程在d=∞时能再现大多数已知的U=∞ Hubbard模型的低能特性。在二维情况下,我们能够研究超交换J引起的变异性。所得的Dyson自能被发现是动量依赖的,如预期。计算了密度和温度依赖的准粒子权重、衰减率以及布里渊区上的峰谱高度。我们还计算了电阻率、霍尔电导率和霍尔角余切值,以实验相关单位呈现。这些结果显示出在密度n>~0.8时显著的热敏感性,表明一个有效的费米液体温度标度,比原始带宽低两到三个数量级。翻转次近邻跃迁t'的符号,即研究空穴与电子掺杂,发现低温度下温度依赖的电阻率曲率从凸变到凹。我们的结果为理解强相关电子掺杂和空穴掺杂物质的温度依赖电阻率差异提供了自然的途径。

英文摘要:

Low energy properties of the metallic state of the 2-dimensional tJ model are presented at various densities and temperatures for second neighbor hopping t', with signs that are negative or positive corresponding to hole or electron doping. The calculation employs a closed set of equations for the Greens functions obtained from the extremely correlated Fermi liquid theory. These equations, when used in $d=\infty$ reproduce most of the known low energies features of the $U=\infty$ Hubbard model. In 2-dimensions we are able to study the variations due to the superexchange J. The resulting Dyson self energy is found to be momentum dependent as expected. The density and temperature dependent quasiparticle weight, decay rate and the peak spectral heights over the Brillouin zone are calculated. We also calculate the resistivity, Hall conductivity and cotangent of the Hall angle in experimentally relevant units. These display significant thermal sensitivity for density n >~ 0.8, signifying an effective Fermi-liquid temperature scale which is two or three orders of magnitude below the bare bandwidth. Flipping the sign of the hopping t', i.e. studying hole versus electron doping, is found to induce a change in curvature of the temperature dependent resistivity from convex to concave at low temperatures. Our results provide a natural route for understanding the observed difference in the temperature dependent resistivity of strongly correlated electron-doped and hole-doped matter.

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