Ground-state and spectral properties of an asymmetric Hubbard ladder

Abstract

We investigate a ladder system with two inequivalent legs, namely a Hubbard chain and a one-dimensional electron gas. Analytical approximations, the density matrix renormalization group method, and continuous-time quantum Monte Carlo simulations are used to determine ground-state properties, gaps, and spectral functions of this system at half-filling. Evidence for the existence of four different phases as a function of the Hubbard interaction and the rung hopping is presented. First, a Luttinger liquid exists at very weak interchain hopping. Second, a Kondo-Mott insulator with spin and charge gaps induced by an effective rung exchange coupling is found at moderate interchain hopping or strong Hubbard interaction. Third, a spin-gapped paramagnetic Mott insulator with incommensurate excitations and pairing of doped charges is observed at intermediate values of the rung hopping and the interaction. Fourth, the usual correlated band insulator is recovered for large rung hopping. We show that the wavenumbers of the lowest single-particle excitations are different in each insulating phase. In particular, the three gapped phases exhibit markedly different spectral functions. We discuss the relevance of asymmetric two-leg ladder systems as models for atomic wires deposited on a substrate.

published version

References in corpus (8)

• Continuous-time Monte Carlo methods for quantum impurity models
• Quantum Phase Transitions and Bipartite Entanglement
• Pair Density Wave correlations in the Kondo-Heisenberg Model
• Entropic analysis of quantum phase transitions from uniform to spatially inhomogeneous phases
• Block Lanczos density-matrix renormalization group method for general Anderson impurity models: Application to magnetic impurity problems in graphene
• Density-matrix renormalization group methods for momentum- and frequency-resolved dynamical correlation functions
• Spinful fermionic ladders at incommensurate filling: Phase diagram, local perturbations, and ionic potentials
• Pair Density Waves in coupled doped two-leg Ladders

Cited by in corpus (9)

• Magnetic excitation spectra of strongly correlated quasi-one dimensional systems: Heisenberg versus Hubbard-like behavior
• Correlated atomic wires on substrates. I. Mapping to quasi-one-dimensional models
• Correlated atomic wires on substrates. II. Application to Hubbard wires
• Correlations and confinement of excitations in an asymmetric Hubbard ladder
• Pair binding and enhancement of pairing correlations in asymmetric Hubbard ladders
• Effective narrow ladder model for two quantum wires on a semiconducting substrate
• Magnetic properties of alternating Hubbard ladders
• Enhanced pair-density-wave vertices in a bilayer Hubbard model at half-filling
• Influence of oxygen orbitals and boundary conditions on the pairing behavior in the Emery model for doped ladders