论文标题
半满的兰道级
The Half-Full Landau Level
论文作者
论文摘要
在均匀的降级器中，兰道级填充分数，例如$ν= 1/2 $，在大多数情况下，地面状态没有能量差距，并且在霍尔电导中没有量化的高原。然而，各州表现出非平凡的低能现象。在过去的几年中，有关这些系统正确描述的正确描述引起了人们的重新关注。 $ν= 1/2 $的问题包括粒子 - 孔对称性的后果，应在限制的旋转对齐系统中存在，在该系统中可以忽略Landau级别之间的混合。其他问题涉及各向异性和几何形状，非零温度的特性以及相对强的疾病的影响。如果确实找到了一个均匀的这个量化者量化的霍尔状态，例如$ν= 5/2 $在GAAS结构中，则对量子状态的性质产生了重大问题，这将在本章中简要讨论。本章还将讨论在半填充附近的两个组件系统中可能发生的现象，即当总填充因子$ν_ {\ rm {tot}} $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 $ν_{\rm{tot}} $ is close to 1.
