论文标题

Weyl/Multi-Weyl和Nodal-line半法的浮点传输通过时间周期势井

Floquet transmission in Weyl/multi-Weyl and nodal-line semimetals through a time-periodic potential well

论文作者

Bera, Sandip, Sekh, Sajid, Mandal, Ipsita

论文摘要

在介观物理学中,时间周期性驱动的应用导致了新型的运输行为,这在静态方案中不存在。在这里,我们考虑了一种量子抽水方案,以便将Weyl/多河和Nodal-Line半金属的准颗粒受到时间周期性的矩形电势。频率$ω$的振荡潜力的存在会产生较高的浮子侧带,并用间距$ \ hbarω$。结果,当Fermi能量的差异(即事件准粒子的能量)以及井的(Quasi)绑定状态水平之一的能量与整数光子的能量相吻合时,就会观察到FANO共鸣。使用Floquet理论和散射矩阵方法,在零温度非绝热泵送极限中,我们在传输系数中发现了特征性的Fano共振模式,这取决于分散性的性质。抽水噪声谱中的拐点也可以作为相应的Fano共振的代理。因此,我们还数字评估了泵送的射击噪声。最后,我们通过明确计算静态井的结合状态(这是驱动系统的结合状态的子集),将FANO共振的存在与井的(准)结合状态相关联。由于我们考虑具有各向异性分散体的半法子,因此观察到的所有特征都取决于电势孔的方向。我们认为,我们的结果将是未来研究非平衡环境中量子传播的指南。

In mesoscopic physics, the application of a time-periodic drive leads to novel transport behaviour, which is absent in the static regimes. Here we consider a quantum pumping protocol, such that the quasiparticles of Weyl/multi-Weyl and nodal-line semimetals are subjected to a time-periodic rectangular potential well. The presence of an oscillating potential of frequency $ω$ creates equispaced Floquet side-bands with spacing $\hbar ω$. As a result, a Fano resonance is observed when the difference in the Fermi energy (i.e., the energy of the incident quasiparticle), and the energy of one of the (quasi)bound state levels of the well, coincides with the energy of an integer number of photons (each carrying energy quantum $\hbar ω$, equal to the side-band spacing). Using the Floquet theory and the scattering matrix approach, in the zero-temperature non-adiabatic pumping limit, we find characteristic Fano resonance patterns in the transmission coefficients, which depend on the nature of the dispersion. The inflection points in the pumped shot noise spectra also serve as a proxy for the corresponding Fano resonances. Therefore, we also numerically evaluate the pumped shot noise. Finally, we correlate the existence of the Fano resonance points to the (quasi)bound states of the well, by explicitly calculating the bound states of the static well (which are a subset of the bound states of the driven system). Since we consider semimetals with anisotropic dispersions, all the features observed depend on the orientation of the potential well. We believe that our results will serve as a guide for future experiments investigating quantum transmission in nonequilibrium settings.

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