Competition between antiferromagnetic and charge order in the Hubbard-Holstein model

Abstract

Sec. IV. Before that in Sec. III, we discuss the global phase diagram, the order parameters and static quantities and their dependence on U, , and 0 . Section V explores the normal state properties of the HH model which helps to understand the ground-state phase diagram and transition. In Sec. VI we discuss how the bosonic properties are modified by the coupling to the electronic system. In Sec. VII we present results for the electronic and bosonic spectral functions, before concluding in Sec. VIII.

Determinant quantum Monte Carlo study of the two-dimensional single-band Hubbard-Holstein model

“…12 shows some differences from the results of infinite dimension DMFT. 70 Generically we see the growth in double occupancy occurring much more gradually than the DMFT result for the largest values of U . This appears to be the case regardless of the underlying state (charge ordered or normal) assumed in the DMFT calculations.…”

“…These results are in contrast to the results obtained in infinite dimensions and T = 0 where a first order AFM/CDW transition has been proposed. 69,70 At this stage it is unclear what role dimension and temperature are playing, indicating the need for further studies.…”

“…When both interactions are present the tendency towards these incompatible orders clearly will compete. [69][70][71][72][73] Competing orders in correlated systems is a prominent issue and a common theme in many transition metal oxides where novel physics often emerges at the boundary between orders.…”

“…[69][70][71][72] Recently this work was extended and a finite temperature phase diagram was proposed for the twodimensional (2D) case at half-filling using determinant quantum Monte Carlo (DQMC). 73 Fig.…”

Electrons of alkali metals in regular nanospaces of zeolites

“…This means that the Mott insulator phase is robust against the deviation from the just half-filled condition in the presence of the finite electron-phonon interaction. Fruitful results at U ≈ S with rather small t (the lower-central area of the t-U-S triangle) have been expected near the half-filled condition [81][82][83], and more reliable calculations have been given by the dynamical mean-field theory [72,73,[87][88][89][90][91][92]. Large bipolarons at U ≈ S may play an important role in superconductivities [72,73,[87][88][89][90]92].…”