Investigating structural distortions in Bi based superconductors by scanning tunneling microscopy
ORAL
Abstract
We use scanning tunneling microscopy to image symmetry-breaking structural distortions in the bismuth-based high-Tc superconductors, Bi$_{2}$Sr$_{2}$Ca$_{n-1}$Cu$_{n}$O$_{2n+4+x}$ (BSCCO). To elucidate the structure, we have implemented a new algorithm that quantifies atomic distortions with picometer resolution. Using this algorithm, we have observed an in-plane inversion-symmetry-breaking orthorhombic structural distortion in the BiO layer. We have also quantified the lattice distortions resulting from the use of Pb substitution to suppress the supermodulation in BSCCO. Each of these structural distortions break point group symmetries of the CuO$_{2}$ plaquette, which may be generally relevant to understanding the broken symmetries of the mysterious pseudogap state in high-Tc cuprates.
*We acknowledge support from NSERC (DMR-0847433), A*STAR, NDSEG and NSERC.
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