Linear-In Temperature Resistivity From Isotropic Planckian Scattering Rate

Published September 22, 2021

In a magnetic field (red arrow), electrons, shown schematically in blue, move in orbits.

Electrons in metals behave like chaotic bumper cars, crashing into each other at every opportunity. While they may be reckless drivers, this result demonstrates that this chaos has a limit established by the laws of quantum mechanics. Using the 45T hybrid magnet and a crystal of high-temperature superconducting material, scientists were able to measure this boundary using high fields to bend electron trajectories to their will.

What did scientists discover?

Electrons in metals behave like chaotic bumper cars, crashing into each other with great frequency. While they may be reckless drivers, this new result demonstrates that this chaos has a limit established by the laws of quantum mechanics.

Why is this important?

MagLab users studied the strange metal phase of a high-temperature superconductor. Superconductivity has the potential to revolutionize the way we carry and store energy, but we still do not understand the workings of the most promising materials for this technology, a fact that delays their applications. The strange metal phase is just one facet of these superconductors, but a facet that plays a key role showing up at a quantum phase transition close to where superconductivity is the strongest. High magnetic fields revealed that the strangeness of these metals is dictated by a limit of physics so far unexplained: the Planckian bound. The Planckian bound limits how often electrons can collide with each other in a metal. Because limits in physics are the guardrails of new concepts, this discovery of the role of the Planckian bound is research that has been stalled for decades.

Who did the research?

G. Grissonnanche^1,2, Y. Fang², A. Legros^1,3, S. Verret¹, F. Laliberté¹, C. Collignon¹, J. Zhou⁴, D. Graf⁵, P. A. Goddard⁶, Louis Taillefer^1,7 & B. J. Ramshaw^2,7

¹Université de Sherbrooke; ²Cornell University; ³Université Paris-Saclay; ⁴University of Texas at Austin; ⁵National High Magnetic Field Laboratory; ⁶University of Warwick; ⁷Canadian Institute for Advanced Research

Why did they need the MagLab?

The 45T hybrid magnet – and the ability to stay at 45T for many hours at a time - was essential to suppress the superconducting state and measure the electron collision rates for many magnetic field orientations and temperatures.