Hole Dynamics in the Orthogonal-Dimer Spin System

TL;DR

This paper explores how doped holes behave in orthogonal-dimer spin systems across different dimensions, revealing conditions for quasi-particle formation and localization, with implications for understanding magnetic and electronic properties.

Contribution

It introduces a combined bond-operator and self-consistent Born approximation method to analyze hole dynamics in various dimensional orthogonal-dimer systems, highlighting the effects of interchain and interlayer couplings.

Findings

Dispersive quasi-particle states exist in the dimer phase even in quasi-two-dimensional systems.

Holes in the plaquette-singlet phase tend to be localized with minimal itinerancy.

Interlayer coupling can enhance the quasi-particle weight in the dimer phase.

Abstract

The dynamics of a doped hole in the orthogonal-dimer spin system is investigated systematically in one, two and three dimensions. By combining the bond-operator method with the self-consistent Born approximation, we argue that a dispersive quasi-particle state in the dimer phase is well defined even for quasi-two-dimensional systems. On the other hand, a doped hole in the plaquette-singlet phase hardly itinerates, forming an almost localized mode. We further clarify that although the quasi-particle weight in the dimer phase is decreased in the presence of the interchain coupling, it is not suppressed but even enhanced upon the introduction of the interlayer coupling.