Random singlet-like phase of disordered Hubbard chains

Abstract

Local moment formation is ubiquitous in disordered semiconductors such as Si:P, where it is observed both in the metallic and the insulating regimes. Here, we focus on local moment behavior in disordered insulators, which arises from short-ranged, repulsive electron-electron interactions. Using density matrix renormalization group and strong-disorder renormalization group methods, we study paradigmatic models of interacting insulators: one dimensional Hubbard chains with quenched randomness. In chains with either random fermion hoppings or random chemical potentials, both at and away from half-filling, we find exponential decay of charge and fermion 2-point correlations but power-law decay of spin correlations that are indicative of the random singlet phase. The numerical results can be understood qualitatively by appealing to the large-interaction limit of the Hubbard chain, in which a remarkably simple picture emerges.

References in corpus (9)

• The Hubbard Model
• Metal-insulator transition in two-dimensional electron systems
• Nearest neighbor tight binding models with an exact mobility edge in one dimension
• Disorder-Driven Non-Fermi Liquid Behavior of Correlated Electrons
• Scaling of Entanglement Entropy in the Random Singlet Phase
• Correlation amplitude and entanglement entropy in random spin chains
• Interaction-induced metallicity in a two-dimensional disordered non-Fermi liquid
• Valence-bond theory of highly disordered quantum antiferromagnets
• Strongly disordered Hubbard model in one dimension: spin and orbital infinite randomness and Griffiths phases

Cited by in corpus (2)

• Random free-fermion quantum spin chain with multi-spin interactions
• Scaling of entanglement entropy at quantum critical points in random spin chains