Peeking Inside a Superconductor

Thomas F. Rosenbaum, University of Chicago, DMR 0907025

The electrons inside a superconductor transmit current with no resistance. This is wonderful for applications, but it prevents any measurements of how the electrons are ordered using electronic means. NbSe2 is a two-dimensional material where the electron waves self organize themselves at T=33K before going superconducting at 7K. But what happens inside the superconductor? We cool down a tiny single crystal and probe it with x-rays to see. As we squeeze it inside a diamond anvil cell we are able to disrupt the organization of the electron waves and explore the competing tendencies of charge-density-wave order and electron pairing in the superconductor.

Phase diagram of NbSe2

as a function of pressure, showing coincident (green) charge density wave and superconducting states.Inset is a picture of the crystal (top) and two manometersinside the diamond anvil cell.

Peeking Inside a Superconductor

Thomas F. Rosenbaum , University of Chicago, DMR 0907025

Freezing bananas and balloons in liquid nitrogen vividly illustrates the concepts of structure, strength, air pressure, and phase transitions, but it also introduces students to the tools used and approaches taken by scientists to investigate the world around us. And when the ice cream emerges from the liquid nitrogen in a matter of minutes, everyone is rewarded! Students watch demonstrations, tour laboratories, talk to scientists, and participate in experiments as part of the University of Chicago’s engagement with schools and community.

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Low temperature physics both entertains and introduces scientific experimentation