Islam Mijanur, Basu Saurabh
Department of Physics, Indian Institute of Technology-Guwahati, Guwahati 781039, India.
J Phys Condens Matter. 2025 Apr 24;37(20). doi: 10.1088/1361-648X/adcdb3.
In this work, we investigate an-lattice in the form of a Corbino disk, characterized by inner and outer radiiand, threaded by a tunable magnetic flux. Through exact (analytic) solution of the stationary Dirac-Weyl equation, we compute the transmission probability of the carriers and hence obtain the conductance features for0<α⩽1(denotes the strength of the hopping between the central atom and one of the other two) which allows ascertaining the role of the flat band, alongwith scrutinizing the transport features from graphene to a dice lattice. Our results reveal periodic Aharonov-Bohm (AB) oscillations in the conductance, reminiscent of the utility of the Corbino disk as an electron pump. Further, these results are strongly influenced by parameters, such as, doping level, ratio of the inner and outer radii, magnetic flux, and. Additionally, complex quantum interference effect resulting in the possible emergence of higher harmonic modes and split-peak structures in the conductance, become prominent for smallervalues and larger ratios of the radii. We also find that, away from the charge-neutrality point (zero doping), the conductance oscillations are more pronounced and sensitive to the various parameters, with the corresponding behavior largely governed via the evanescent wave transport. Further, the Fano factor reveals distinct transport regimes, transitioning from Poissonian to pseudo-diffusive for < 1, and from ballistic to pseudo-diffusive at the dice limit ( = 1). Thus, this setup serves as a fertile ground for studying the generation of quantum Hall current and AB oscillations in a flat band system, alongwith demonstrating intricate appearance of higher harmonics in the electron transport. Finally, to put things in perspective, we have compared our results with those for graphene disks that highlight the difference between the two with regard to device applications.
在这项工作中，我们研究了一种呈科尔比诺圆盘形式的an晶格，其特征在于具有内半径和外半径，并由可调谐磁通量穿过。通过对稳态狄拉克-外尔方程的精确（解析）求解，我们计算了载流子的传输概率，从而获得了0<α⩽1（表示中心原子与另外两个原子之一之间的跳跃强度）时的电导特性，这使得我们能够确定平带的作用，同时仔细研究从石墨烯到骰子晶格的输运特性。我们的结果揭示了电导中的周期性阿哈罗诺夫-玻姆（AB）振荡，这让人想起科尔比诺圆盘作为电子泵的效用。此外，这些结果受到诸如掺杂水平、内半径与外半径之比、磁通量等参数的强烈影响。此外，对于较小的α值和较大的半径比，导致电导中可能出现高次谐波模式和分裂峰结构的复杂量子干涉效应变得更加显著。我们还发现，远离电荷中性点（零掺杂）时，电导振荡更加明显且对各种参数更敏感，相应的行为在很大程度上由倏逝波输运决定。此外，法诺因子揭示了不同的输运区域，对于α<1从泊松分布转变为伪扩散，在骰子极限（α = 1）时从弹道输运转变为伪扩散。因此，这种设置为研究平带系统中的量子霍尔电流产生和AB振荡提供了一个丰富的平台，同时展示了电子输运中高次谐波的复杂出现。最后，为了全面看待问题，我们将我们的结果与石墨烯圆盘的结果进行了比较，突出了两者在器件应用方面的差异。
