论文标题
二维系统中磁振荡的一般公式
A general formulation for the magnetic oscillations in two dimensional systems
论文作者
论文摘要
我们在二维（2D）系统中开发了磁振荡（MO）的一般形式主义。我们考虑一般的2D Landau水平，除垂直磁场外，可能取决于其他变量或指数。在基态下，我们获得了MO相和振幅的表达式。由此，我们使用傅立叶扩展来编写MO，第一项是锯齿振荡。我们还考虑了有限温度，杂质或晶格缺陷的影响，假设兰道水平的一般扩大。我们开发了两种描述MO中这些阻尼效应的方法。一个在Landau水平的占用方面，另一个在还原因素方面，这导致Lifshits-Kosevich（LK）公式的概括。我们表明，当只有接近费米能量的状态被激发时，第一种方法在非常低的阻尼中特别有用。相比之下，在谐波扩展中只需要很少的术语时，LK公式可能更方便。我们比较不同的阻尼情况，显示了每种情况下MO的宽广方式。提出的一般公式允许将MO的属性与2D系统的属性联系起来。
We develop a general formalism for the magnetic oscillations (MO) in two dimensional (2D) systems. We consider general 2D Landau levels, which may depend on other variable or indices, besides the perpendicular magnetic field. In the ground state, we obtain expressions for the MO phase and amplitude. From this we use a Fourier expansion to write the MO, with the first term being a sawtooth oscillation. We also consider the effects of finite temperature, impurities or lattice imperfections, assuming a general broadening of the Landau levels. We develop two methods for describing these damping effects in the MO. One in terms of the occupancy of the Landau levels, the other in terms of reduction factors, which results in a generalization of the Lifshits-Kosevich (LK) formula. We show that the first approach is particularly useful at very low damping, when only the states close to the Fermi energy are excited. In contrast, the LK formula may be more convenient at higher damping, when only few terms are needed in its harmonic expansion. We compare different damping situations, showing how the MO are broadened in each case. The general formulation presented allows to relate the properties of the MO with those of the 2D systems.
