Theory of spin excitations in undoped and underdoped cuprates
Theory of spin excitations in undoped and underdoped cuprates
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DOI：
10.1006/aphy.1998.5888
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发表时间：
1998-10
影响因子：
3
通讯作者：
Don H. Kim;P. Lee
中科院分区：
文献类型：
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作者：
Don H. Kim;P. Lee
摘要本文从规范理论的角度考虑了高温度铜酸盐的磁性能，重点研究了欠掺杂状态。欠掺杂的铜酸盐具有一定的反铁磁相关性，例如，Cu和O位点的核磁共振弛豫速率的不同温度依赖性证明了这一点，而t - J模型的从玻色子平均场理论并没有很好地捕捉到这一点。我们证明了规范波动的加入将弥补平均场理论的不足。作为反铁能量相关的规范涨落恢复和1/ N微扰理论的可行性的一个具体例证，我们用无质量狄拉克费米子的1+1D U(1)规范理论对海森堡自旋链进行了分析。同一规范理论在2+1D中的1/ N -微扰处理（可以从海森堡模型的平均场π -通量相位激发）导致与反铁磁有序相对应的动态质量生成。另一方面，我们认为在一个与玻色（holon）场附加耦合的类似规范理论中，对称破缺不会发生，但反铁磁相关性得到增强，这就是低掺杂铜酸盐的情况。
Abstract We consider the magnetic properties of high T c cuprates from a gauge theory point of view, with emphasis on the underdoped regime. Underdoped cuprates possess certain antiferromagnetic correlations, as evidenced, for example, by different temperature dependence of the Cu and O site NMR relaxation rates, that are not captured well by slave boson mean field theories of the t - J model. We show that the inclusion of gauge fluctuations will remedy the deficiencies of the mean field theories. As a concrete illustration of the gauge-fluctuation restoration of the antiferromangetic correlation and the feasibility of the 1/ N perturbation theory, the Heisenberg spin chain is analyzed in terms of a 1+1D U(1) gauge theory with massless Dirac fermions. The 1/ N -perturbative treatment of the same gauge theory in 2+1D (which can be motivated from the mean field π -flux phase of the Heisenberg model) leads to a dynamical mass generation corresponding to an antiferromagnetic ordering. On the other hand, it is argued that in a similar gauge theory with an additional coupling to a Bose (holon) field, symmetry breaking does not occur, but antiferromagnetic correlations are enhanced, which is the situation in the underdoped cuprates.