论文标题
复合费米斯的费米表面
Fermi surfaces of composite fermions
论文作者
论文摘要
将近四十年前的二维电子系统中发现了分数量子厅（FQH）效应。它帮助启动了拓扑阶段的领域，此外，由于动能的淬火，它给了“相关物质”一词的新含义。大多数FQH阶段都像绝缘子和超导体一样夹住。但是，发现以NU = 1/2为代表的Landau水平的均匀分母NU的小子集被发现是无间隙的，具有类似于金属的费米表面。我们讨论了我们的结果，使用无限密度基质重新归一化组（IDMRG）方案进行数值获得，该方案对非异端畸变的影响，在相关= 1/2个状态的相关nu = 1/2个状态的Fermi表面上，在零磁场上，费米表面的离散n倍旋转对称性在零磁场上。我们发现，虽然n = 2（椭圆形）畸变的响应显着（并且与无可调参数的实验观测值一致），但随着n的增加，它会非常快速减少。还发现了其他异常，例如将费米表面分为不相交的弹性。这突出了由动能形成的费米表面与在哈密顿量中纯粹的能量项形成的费米表面之间的差异。
The fractional quantum Hall (FQH) effect was discovered in two-dimensional electron systems subject to a large perpendicular magnetic field nearly four decades ago. It helped launch the field of topological phases, and in addition, because of the quenching of the kinetic energy, gave new meaning to the phrase "correlated matter". Most FQH phases are gapped like insulators and superconductors; however, a small subset with even denominator fractional fillings nu of the Landau level, typified by nu = 1/2, are found to be gapless, with a Fermi surface akin to metals. We discuss our results, obtained numerically using the infinite Density Matrix Renormalization Group (iDMRG) scheme, on the effect of non-isotropic distortions with discrete N-fold rotational symmetry of the Fermi surface at zero magnetic field on the Fermi surface of the correlated nu = 1/2 state. We find that while the response for N = 2 (elliptical) distortions is significant (and in agreement with experimental observations with no adjustable parameters), it decreases very rapidly as N is increased. Other anomalies, like resilience to breaking the Fermi surface into disjoint pieces, are also found. This highlights the difference between Fermi surfaces formed from the kinetic energy, and those formed of purely potential energy terms in the Hamiltonian.
