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[Emeriti-faculty] Reminder: Physics and Astronomy Colloquium today

Good morning:

There is a Physics and Astronomy Cooloquium today - details below.

Friday, December 5, 2008
3:00 PM
Anderson 206

Tufts University
Physics and Astronomy Colloquium

?Unsolved Mysteries: Electron Pairing in High Temperature Superconductors?

Dr. Vidya Madhavan
Boston College

The electron-electron interaction is normally repulsive. In some
materials at low temperatures, this repulsive force is defeated and
electrons feel an attractive force that binds them into pairs. It is
the formation of these pairs that creates a zero resistance material: a
superconductor. We now know that the miracle glue that binds electrons
into pairs in conventional superconductors is phonons. But after two
decades of intense research on high-temperature (high-Tc)
superconductors, there is no consensus on the basic question: what is
the mechanism that causes electron pairing? The ?high-Tc problem?
remains one of the most important outstanding problems in condensed
matter physics today. Even as we explore the possibility that pairing
in these unconventional superconductors proceeds without the
involvement of a bosonic glue, we have recently made exciting progress
in identifying candidates that could potentially mediate pairing. I
will present low temperature scanning tunneling microscopy data on the
high-Tc superconductor Pr0.88LaCe0.12CuO4 (PLCCO) where we have
discovered a bosonic mode at energies of 10.5±2.5 meV. I will discuss
the possible origins of this mode and its implications for the pairing
mechanism of the high-Tc superconductors.

Refreshments at 2:30 PM in Knipp Library, Robinson 251