We have used resonant soft x-ray scattering to study the effects of discommensuration on the hole Wigner crystal (HC) in the spin ladder Sr14-xCaxCu24O41 (SCCO). As the hole density is varied the HC forms only with the commensurate wave vectors LL=1/5 and LL=1/3; for incommensurate values it "melts." A simple scaling between LL and temperature is observed, τ1/3/τ1/5=5/3, indicating an inverse relationship between the interaction strength and wavelength. Our results suggest that SCCO contains hole pairs that are crystallized through an interplay between lattice commensuration and Coulomb repulsion, reminiscent of the "pair density wave" scenario.
ASJC Scopus subject areas
- Physics and Astronomy(all)