发表机构
University of Maryland（马里兰大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该论文解析计算了二维电子气静态屏蔽的交换自能和顶点修正，发现其和有限并重整化Thomas-Fermi波矢，将Kohn扭结变为双侧峰，增强Friedel振荡，并讨论了对Kohn-Luttinger配对的影响。
AI 中文摘要
我们解析计算了二维（2D）电子气静态不可极化率的领先阶环图修正，即两个交换自能图和交换顶点图，每个图在库仑耦合中均为第一阶，并将所得极化率代入RPA几何级数，以获得静态介电函数和屏蔽相互作用。自能和顶点贡献各自发散；我们以闭式形式得到了两个发散部分。它们的和是有限的，并精确重现了Hartree-Fock压缩率，该压缩率对Thomas-Fermi波矢进行了重整化。我们证明交换作用将2D Kohn扭结在2k_F处从单侧转变为尖锐的双侧峰，这是对Thomas-Fermi和RPA屏蔽的定性改进。在实空间中，这使得带电杂质周围的Friedel振荡比RPA中的大2-3倍，且在所研究的距离范围内振幅随距离增加而增大；讨论了其对Kohn-Luttinger配对的影响。还讨论了与早期关于相同图的工作的关系。
英文摘要
We compute analytically the leading beyond-ring corrections to the static irreducible polarizability of the two-dimensional (2D) electron gas, namely the two exchange self-energy diagrams and the exchange vertex diagram, each of first order in the Coulomb coupling, and insert the resulting polarizability into the RPA geometric series to obtain the static dielectric function and screened interaction. The self-energy and vertex contributions individually diverge; we obtain both divergent pieces in closed form. Their sum is finite and reproduces exactly the Hartree-Fock compressibility, which renormalizes the Thomas-Fermi wave vector. We show that exchange converts the one-sided 2D Kohn kink at 2k_F into a sharp two-sided peak, a qualitative improvement over Thomas-Fermi and RPA screening. In real space this makes the Friedel oscillations around a charged impurity 2-3 times larger than in RPA, with an amplitude that increases with distance over the range studied; implications for Kohn-Luttinger pairing are discussed. Relation to earlier works on the same diagrams is discussed.
Comments10 pages, 6 figures, 3 tables
