标题： 动态极化、等离子体模型以及掺杂狄拉克和外尔系统中屏蔽势的弗里德尔振荡 显示英文标题

标题： Dynamical polarization, plasmon model, and the Friedel oscillation of the screened potential in doped Dirac and Weyl system

摘要： 我们讨论了二维狄拉克系统和三维外尔系统（存在能隙）在低能紧束缚模型中的动态极化、等离子体色散、弛豫时间和屏蔽势的弗里德尔振荡。 所得结果，如费米波矢、托马斯-费米波矢和纵向电导率，在不同维度中得到。 本文详细讨论了一些重要结论，包括在短程或长程库仑相互作用下的屏蔽特性，以及二维或三维情况下的纵向电导率。 在光学极限下，二维系统和三维系统的纵向电导率具有明显区别。 费米波矢、直流电导率和弛豫时间的密度依赖性（包括载流子密度和杂质浓度）被讨论。 特别地，对于掺杂的外尔系统，由于电磁响应产生的手征异常引起的注入载流子密度由节点内弛豫时间控制，该时间也已进行分析。 %计算所基于的模型是如第二部分所述的低能紧束缚模型，%即本文的结果适用于低温和低能情况%因此可以如文中所述对弛豫时间进行对数自能修正。 %几种系统中纵向电导率的差异也进行了讨论。 我们的结果有助于狄拉克或外尔系统的应用以及它们低温特性的研究。 显示英文摘要

摘要： We discuss the dynamical polarization, plasmon dispersion, relaxation time, and the Friedel oscillation of screened potential of the two-dimension Dirac and three-dimension Weyl system (which are gapped) in the low-energy tigh-binding model. The results, like the Fermi wavevector, Thomas-Fermi wavevector, and longitudinal conductivity are obtained in different dimensions. Some important conclusions are detailedly discussed in this paper, including the screening character under short or long range Coulomb interaction, and the longitudinal conductivity in two- or three-dimensions. The longitudinal conductivity in optical limit is distinguishing for the case of two-dimension system and three-dimension system. The density-dependence (including the carrier density and the impurity concentration) of the Fermi wavevector, dc conductivity, and the relaxation time are discussed. Specially, for the doped Weyl system, the pumped carrier density due to the chiral anomaly origin from electromagnetic response is controlled by the internode relaxation time which has also been analyzed. %The model for which the calculations based on is the low-energy tight-binding model as presented in the Sec.2, %i.e., the results in this paper is for the low-temperature and low-energy case %and it's thus possible to carrying out a logarithmic self-energy correction to the relaxation time as we discussed in the text. %The difference between the longitudinal conductivity in serversal systems is also been discussed. Our results is helpful to the application of the Dirac or Weyl systems as well as the study on their low-temperature characters.