Broken particle-hole symmetry at atomically flat a-axis YBa2Cu3O7-d interfaces

Abstract

We have studied quasiparticle tunneling into atomically flat a-axis films of YBa2Cu3O7-d and DyBa2Cu3O7-d through epitaxial CaTiO3 barriers. The junction heterostructures were grown by oxide molecular beam epitaxy and were carefully optimized using in-situ monitoring techniques, resulting in unprecedented crystalline perfection of the superconductor/insulator interface. Below Tc, the tunneling conductance shows the evolution of a large unexpected asymmetrical feature near zero bias. This is evidence that superconducting YBCO crystals, atomically truncated along the lobe direction with a titanate layer, have intrinsically broken particle-hole symmetry over macroscopically large areas.

15 pages, 4 figures; v2 includes minor changes in concluding paragraph to match PRL version

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Cited by in corpus (2)

• Electron sampling depth and saturation effects in perovskite films investigated by soft x-ray absorption spectroscopy
• a-axis YBa2Cu3O7-x/PrBa2Cu3O7-x/YBa2Cu3O7-x trilayers with subnanometer rms roughness