Dynamics of lattice pinned charge stripes

TL;DR

This paper investigates how quantum fluctuations can depin charged stripes from a lattice, analyzing the transition from pinned to free movement depending on the hopping amplitude and string tension, with implications for quantum string dynamics.

Contribution

It introduces a model for the quantum depinning of charge stripes, mapping it onto Josephson junctions and sine-Gordon theory, providing a quantitative depinning threshold and excitation spectrum analysis.

Findings

Quantum fluctuations can depin charge stripes at t/J = 2 / pi^2.

The system maps onto a 1D Josephson junction array.

The infrared excitation spectrum is calculated for all t/J values.

Abstract

We study the transversal dynamics of a charged stripe (quantum string) and show that zero temperature quantum fluctuations are able to depin it from the lattice. If the hopping amplitude t is much smaller than the string tension J, the string is pinned by the underlying lattice. At t>>J, the string is depinned and allowed to move freely, if we neglect the effect of impurities. By mapping the system onto a 1D array of Josephson junctions, we show that the quantum depinning occurs at t/J = 2 / pi^2. Besides, we exploit the relation of the stripe Hamiltonian to the sine-Gordon theory and calculate the infrared excitation spectrum of the quantum string for arbitrary t/J values.