arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1202.5586cond-mat.mes-hallcond-mat.str-el
收藏

分数量子Hall系统的能带质量各向异性和内禀度规

Band mass anisotropy and the intrinsic metric of fractional quantum Hall systems

Bo Yang, Z. Papić, E. H. Rezayi, R. N. Bhatt, F. D. M. Haldane

摘要:

最近有人指出,拓扑液相中产生的分数量子霍尔效应(量子霍尔效应)不需要是旋转不变的,因为大多数变分波函数提出的日期已经。相反,它们具有对应于剪切变形的几何自由度,其作用类似于内在度量。我们将这个想法应用到一个系统的各向异性带质量,本质上是在多谷半导体,如AlAs和Si,或在各向同性系统,如GaAs中存在的倾斜磁场,这打破了旋转不变性的情况下。我们进行精确的对角化计算与周期性的边界条件(环面几何)的各种填充分数在最低,第一和第二朗道水平。在最低的朗道水平,我们表明,一般生存的旋转不变性的带质量各向异性的中等值的故障的ESTHE状态。在1/3填充,我们生成一个变分家庭的Laughlin波函数参数化的度量自由度。我们发现,调整的内在度量的劳克林状态的带质量各向异性或介电张量的变化,而相位保持稳健。在n=1朗道水平,质量各向异性驱动不可压缩液体和可压缩状态之间的电荷密度波有序的过渡。在n>=2朗道能级,质量各向异性选择和增强条纹有序与兼容的波矢量在部分1/3和1/2填充。

英文摘要:

It was recently pointed out that topological liquid phases arising in the fractional quantum Hall effect (FQHE) are not required to be rotationally invariant, as most variational wavefunctions proposed to date have been. Instead, they possess a geometric degree of freedom corresponding to a shear deformation that acts like an intrinsic metric. We apply this idea to a system with an anisotropic band mass, as is intrinsically the case in many-valley semiconductors such as AlAs and Si, or in isotropic systems like GaAs in the presence of a tilted magnetic field, which breaks the rotational invariance. We perform exact diagonalization calculations with periodic boundary conditions (torus geometry) for various filling fractions in the lowest, first and second Landau levels. In the lowest Landau level, we demonstrate that FQHE states generally survive the breakdown of rotational invariance by moderate values of the band mass anisotropy. At 1/3 filling, we generate a variational family of Laughlin wavefunctions parametrized by the metric degree of freedom. We show that the intrinsic metric of the Laughlin state adjusts as the band mass anisotropy or the dielectric tensor are varied, while the phase remains robust. In the n=1 Landau level, mass anisotropy drives transitions between incompressible liquids and compressible states with charge density wave ordering. In n>=2 Landau levels, mass anisotropy selects and enhances stripe ordering with compatible wave vectors at partial 1/3 and 1/2 fillings.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑