Competing orders in NaxCoO2 from strong correlations on a two-particle level | |
Article | |
关键词: ELECTRONIC-STRUCTURE; SUPERCONDUCTIVITY; SYSTEMS; | |
DOI : 10.1103/PhysRevB.85.115128 | |
来源: SCIE |
【 摘 要 】
Based on dynamical mean-field theory with a continuous-time quantum Monte Carlo impurity solver, static as well as dynamic spin and charge susceptibilites for the phase diagram of the sodium cobaltate system NaxCoO2 are discussed. The approach includes important vertex contributions to the q dependent two-particle response functions by means of a local approximation to the irreducible vertex function in the particle-hole channel. A single-band Hubbard model suffices to reveal several charge-and spin-instability tendencies in accordance with experiment, including the stabilization of an effective kagome sublattice close to x = 0.67, without invoking the doping-dependent Na-potential landscape. The in-plane antiferromagnetic-to-ferromagnetic crossover is additionally verified by means of the computed Korringa ratio. Moreover an intricate high-energy mode in the transverse spin susceptiblity is revealed, pointing toward a strong energy dependence of the effective intersite exchange.
【 授权许可】
Free