标题： 第一性原理研究CeCu$_{2}$Si$_{2}$的费米面拓扑结构 显示英文标题

标题： First-Principles Study of the Fermi Surface Topology of CeCu$_{2}$Si$_{2}$

摘要： 自发现CeCu$_{2}$Si$_{2}$中的重费米子超导性以来，该材料引起了极大的兴趣，特别是关于超导配对的本质及其机制。因此，更好地理解电子费米面拓扑结构及其在强反铁磁涨落中的作用至关重要。标准密度泛函理论方法不足以模拟局域4{\it f}-电子中的强局域库仑排斥作用与其与巡游配体轨道电子的杂化之间的相互作用。我们使用Gutzwiller波函数近似对CeCu$_{2}$Si$_{2}$进行了电子基态计算。Gutzwiller近似能够捕捉到由强局域库仑排斥引起的准粒子带重整化。我们通过改变相互作用强度并考虑晶体场分裂，分析了这种效应对电子结构和费米面拓扑结构的影响。利用de Haas van Alphen效应，计算了极值费米面截面面积，以量化准粒子质量重整化对费米面的影响。我们的结果确认了两个费米面片，分别对应于重（488m$_{e}$）和轻（4.35m$_{e}$）准粒子，这与实验测量以及重整化带方法非常一致。 显示英文摘要

摘要： Since the discovery of heavy-fermion superconductivity in CeCu$_{2}$Si$_{2}$, the material has attracted great interest particularly with regard to the nature of the superconducting pairing and its mechanism. Consequently, it is essential to better understand the electronic Fermi surface topology and its role in strong antiferromagnetic fluctuations. The standard density functional theory method is insufficient to model the interplay of strong onsite Coulomb repulsion in localized 4{\it f}-electrons and their hybridization with itinerant ligand-orbital electrons. We have performed electronic ground state calculations on CeCu$_{2}$Si$_{2}$ using the Gutzwiller wavefunction approximation. The Gutzwiller approximation captures the quasiparticle band renormalization from the strong onsite Coulomb repulsion. We have performed an analysis of this effect on the electronic structure and the Fermi surface topology by varying the interaction strength and taking into account the crystal-field splitting. Using the de Haas van Alphen effect, the extremal Fermi surface cross-sectional areas were calculated to quantify the effects of quasiparticle mass renormalization on the Fermi surface. Our results confirm two Fermi surface sheets corresponding to the heavy (488m$_{e}$) and light (4.35m$_{e}$) quasiparticles, which is in close agreement with experimental measurements as well as the renormalized band method.