# Quantum phases of frustrated 2-leg spin-1/2 ladders with skewed rungs

## TL;DR

This study explores the complex quantum phases of frustrated 2-leg spin-1/2 ladders with skewed rungs using exact diagonalization and DMRG, revealing multiple magnetic and bond-order phases depending on interaction parameters.

## Contribution

It provides a detailed phase diagram of frustrated spin ladders with skewed rungs, highlighting the emergence of diverse quantum phases due to frustration and variable exchange interactions.

## Key findings

- Identification of antiferromagnetic and ferromagnetic phases at different interaction strengths.
- Discovery of bond-order-wave and reentrant antiferromagnetic phases.
- Demonstration of complex phase behavior using large-scale numerical methods.

## Abstract

The quantum phases of 2-leg spin-1/2 ladders with skewed rungs are obtained using exact diagonalization of systems with up to 26 spins and by density matrix renormalization group calculations to 500 spins. The ladders have isotropic antiferromagnetic (AF) exchange $J_2 > 0$ between first neighbors in the legs, variable isotropic AF exchange $J_1$ between some first neighbors in different legs, and an unpaired spin per odd-membered ring when $J_1 \gg J_2$. Ladders with skewed rungs and variable $J_1$ have frustrated AF interactions leading to multiple quantum phases: AF at small $J_1$, either F or AF at large $J_1$, as well as bond-order-wave phases or reentrant AF (singlet) phases at intermediate $J_1$.