The Half-Full Landau Level
The Half-Full Landau Level
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半满朗道水平
DOI：
10.1142/9789811217494_0002
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发表时间：
2020
期刊：
影响因子：
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通讯作者：
B. Halperin
中科院分区：
文献类型：
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作者：
B. Halperin
在偶分母朗道能级填充分数（例如 ν = 1/2）下，基态在大多数情况下没有能隙，并且霍尔电导中没有量子化平台。然而，这些态表现出不平凡的低能现象。在过去的几年里，有关这些系统的正确描述的开放性问题再次引起了人们的关注。 ν = 1/2 时的问题包括粒子空穴对称性的后果，这应该存在于自旋对准系统中，在可以忽略朗道能级之间混合的极限内。其他问题涉及各向异性和几何形状、非零温度下的特性以及相对较强的无序效应。如果确实发现了带隙偶分母量子化霍尔态，例如 GaAs 结构中的 ν = 5/2，就会出现有关量子态性质的重大问题，本章将对此进行简要讨论。本章还将讨论接近半填充的双组分系统中可能出现的现象，即当总填充因子 νtot 接近 1 时。
At even-denominator Landau level filling fractions, such as ν = 1/2, the ground state, in most cases, has no energy gap, and there is no quantized plateau in the Hall conductance. Nevertheless, the states exhibit non-trivial low-energy phenomena. Open questions concerning the proper description of these systems have attracted renewed attention during the last few years. Issues at ν = 1/2 include consequences of particle-hole symmetry, which should be present for a spin-aligned system in the limit where one can neglect mixing between Landau levels. Other issues concern questions of anisotropy and geometry, properties at non-zero temperature, and effects of relatively strong disorder. In cases where one does find a gapped even-denominator quantized Hall state, such as ν = 5/2 in GaAs structures, major questions have arisen about the nature of the quantum state, which will be discussed briefly in this chapter. The chapter will also discuss phenomena that can occur in a two-component system near half filling, i.e., when the total filling factor νtot is close to 1.