Chain-oxygen ordering in twin-free YBa2Cu3O6+x single crystals driven by 20 keV electron irradiation

TL;DR

This study investigates how 20 keV electron irradiation influences oxygen atom arrangements in YBa2Cu3O6+x crystals, revealing that electron bombardment can induce oxygen ordering and chain extension without changing overall oxygen content.

Contribution

It demonstrates that electron irradiation causes collective oxygen atom hopping and chain extension in YBa2Cu3O6+x, a novel finding linking electron bombardment to oxygen ordering mechanisms.

Findings

Electron irradiation induces oxygen atom hopping and chain extension.

Oxygen ordering occurs without changing overall oxygen content.

The effect is analogous to photoinduced ordering via charge imbalance.

Abstract

We have examined the effects of 20 keV electron irradiation on [-Cu(1)-O(1)-]n chain oxygen arrangements in oxygen deficient but otherwise twin-free YBa2Cu3O6+x single crystals. Comparison of polarized Raman spectra of non-irradiated and irradiated areas provides evidence that electron bombardments instigate the collective hopping of oxygen atoms either from an interstitial at O(5) site to a vacant O(1) chain site or by reshuffling the chain segments to extend the average length of chains without changing the overall oxygen content. This oxygen ordering effect, while counter-intuitive, is analogous to that found in the photoexcitation induced ordering in which temporal charge imbalance from electron-hole pair creation by inelastic scattering of incident electrons causes a local lattice distortion which brings on the atomic rearrangements.