We theoretically study magnetic field, temperature, and energy band-gap dependences of magnetizations in the Dirac fermions. We use the zeta function regularization to obtain analytical expressions of thermodynamic potential, from which the magnetization of graphene for strong field/low temperature and weak field/high temperature limits are calculated. Further, we generalize the result by considering the effects of impurity on orbital susceptibility of graphene. In particular, we show that in the presence of impurity, the susceptibility follows a scaling law which can be approximated by the Faddeeva function. In the case of the massive Dirac fermions, we show that a large band-gap gives a robust magnetization with respect to temperature and impurity. In the doped Dirac fermion, we discuss the dependence of the band-gap on the period and amplitude of the de Haas-van Alphen effect.
In our work, we study the dynamics of a graphene Corbino disk supported by a gold mechanical resonator in the presence of a magnetic field. We demonstrate here that our graphene/gold mechanical structure exhibits a nontrivial resonance frequency dependence on the applied magnetic field, showing how this feature is indicative of the de Haas-van Alphen effect in the graphene Corbino disk. Our findings are the first evidence of dHvA effect for massless Dirac fermions. By relying on the mechanical resonances of the Au structure, our detection scheme is essentially independent of the material consi…
The strain engineering technique allows us to alter the electronic properties of graphene in various ways. Within the continuum approximation, the influences of strain result in the appearance of a pseudo-gauge field and modulated Fermi velocity. In this study, we investigate theoretically the effect of linear uniaxial tensile strain and/or stress, which makes the Fermi velocity anisotropic, on a magnetized graphene sheet in the presence of an applied electrostatic voltage. More specifically, we analyze the consequences of the anisotropic nature of the Fermi velocity on the structure Landau le…
Quantum Hall conductance and de Haas van Alphen oscillation in a tight-binding model with electron and hole pockets for (TMTSF)$_2$NO$_3$
在（TMTSF）$_2$ NO $_3$的紧束缚模型中，由于负离子在$a$ -方向上的周期性有序势，导致了电子和空穴的小口袋，从理论上研究了量子化霍尔电导和de Haas van Alphen（dHvA）振荡.磁场被跳跃处理为复数，这是由于矢量位引起的相位，即Peierls替换。在参数和磁场的实际值中，获得作为磁场的函数的能量（Hofstadter蝶形图）。结果表明，作为反磁场的函数，能级加宽，带隙周期性地闭合或几乎闭合，这在磁击穿的半经典理论中是看不到的。当化学势处于能隙内时，霍尔电导被量子化为一个由丢番图方程得到的整数。当在该系统中掺杂电子或空穴时，霍尔电导在磁场的某些区域中被量子化，但由于朗道能级的加宽，霍尔电导在磁场的其它区域中不被量子化。零温下dHvA振荡的振幅随磁场的增大而减小，而在半经典的Lifshitz Kosevich公式中dHvA振荡的振幅是常数.
The Anomalous de Haas-van Alphen Effect in InAs/GaSb quantum wells
de Haas-van Alphen效应（dHvAe）描述了作为反向施加的磁场的函数的材料中的磁化强度的周期性振荡。它形成了测量费米表面性质的良好程序的基础，并且它的观察通常被视为系统是金属的直接签名。然而，某些绝缘体可以表现出类似的振荡的磁化从量子化的电子状态的能量在填充带。最近，这种${\it anomalous}$ dHvAe（AdHvAe）的理论已经被提出，但到目前为止还没有明确的实验观察。在这里，我们表明，InAs/GaSb量子阱的倒窄隙制度是一个理想的平台，用于观察的AdHvAe。从我们的微观计算，我们作出定量预测的相关磁场和温度制度，并描述明确的实验签名。
We theoretically study the de Haas-van Alphen (dHvA) oscillations in the system with changing the topology of the Fermi surface (the Lifshitz transition) by electron dopings. We employ the two-dimensional tight binding model for $α$-(BEDT-TTF)$_2$I$_3$ under pressure which has two Dirac points in the first Brillouin zone. When this system is slightly doped, there exists two closed Fermi surfaces with the same area and the dHvA oscillations become saw-tooth pattern or inversed saw-tooth pattern for both cases of fixed electron filling ($ν$) or fixed chemical potential ($μ$) with respect to the …
We report the magneto-transport properties of CaAl$_4$ single crystals with $C2/m$ structure at low temperature. CaAl$_4$ exhibits large unsaturated magnetoresistance $\sim$3000$\%$ at 2.5 K and 14 T. The nonlinear Hall resistivity is observed, which indicates the multi-band feature. The first-principles calculations show the electron-hole compensation and the complex Fermi surface in CaAl$_4$, to which the two-band model with over-simplified carrier mobility can't completely apply. Evident quantum oscillations have been observed with B//c and B//ab configurations, from which the nontrivial Be…
A unique attribute of atomically thin quantum materials is the in-situ tunability of their electronic band structure by externally controllable parameters like electrostatic doping, electric field, strain, electron interactions, and displacement or twisting of atomic layers. This unparalleled control of the electronic bands has led to the discovery of a plethora of exotic emergent phenomena. But despite its key role, there is currently no versatile method for mapping the local band structure in advanced 2D materials devices in which the active layer is commonly embedded in various insulating l…
Effect of structural disorder on quantum oscillations in graphite
我们研究了在温度低至30 mK和磁场高至14 T的条件下，结构无序对单晶和高取向热解石墨样品中测得的de Haas van Alphen（dHvA）和Shubnikov de Haas（SdH）量子振荡的影响。的测量进行了不同的样品，其特征在于通过X射线衍射，透射电子显微镜和原子力显微镜技术。我们的结果揭示了量子振荡的振幅和表面粗糙度之间的相关性。
Intrinsic Perturbation of the Landau Levels in Metals and Semiconductors at Low Temperatures
结果表明，在非超导金属中，很低温度下的de Haas van Alphen效应的频率可被Pauli方程的扩展后的Landau方程中的微扰项所校正。对德哈斯-范-阿尔芬振荡频率的修正依赖于费米能和电子旋磁因子的可测反常部分。此外，研究表明，由于扰动项的影响，在大于25特斯拉的高磁场感应和1毫开量级的超低温下，稀简并费米气体的电子比热Cv表现出异常行为，并且在有限温度下，随着温度接近绝对零度，Cv变得非常小，即Cv约为零。本文提出在低温和高磁场下精确测量简单能带半导体的磁光吸收，作为探测朗道能级修正的直接方法，朗道能级的修正是由于弱微扰项在磁场中修正了电子的动能。
We theoretically investigate the phase of the de Haas - van Alphen oscillations in topological line-node semimetals. In these semimetals the chemical potential of charge carriers can essentially depend on the magnetic field, and this dependence changes the phase of the oscillations as compared to the phase in a three-dimensional metal with a band-contact line. Our results elucidate recent experimental data on the Berry phase for certain electron orbits in ZrSiS, ZrSiTe, and ZrSiSe.
