After a year of trial and error. Liyang Chen had managed to whittle down a metallic wire into a microscopic strand half. The width of an E.coli bacterium — just thin enough to allow a trickle of electric current to pass through. The drips of that current might, Chen hoped. Help settle a persistent mystery about how charge moves through a bewildering class of materials known as strange metals. Chen, then a graduate student, and his collaborators at Rice University measured the current flowing through their atoms-thin strand of metal. And they found that it flowed smoothly and evenly. So evenly, in fact, that it defied physicists’ standard conception of electricity in metals.
A Cuprate Wrench
The first challenge to the conventional Phone Number List understanding of metals came in 1986. When Georg Bednorz and Karl Alex Müller rocked the physics world with their discovery of high-temperature superconductors. Materials that perfectly carry an electric current even at relatively warm temperatures. Familiar metals like tin and mercury become superconductors only when chilled to within a few degrees of absolute zero. Bednorz and Müller measured the electrical resistance in a copper-based (“cuprate”) material and saw that it vanished at a relatively balmy 35 kelvins. (For their breakthrough discovery, Bednorz and Müller pocketed a Nobel Prize just a year later.) A portrait of Douglas Natelson wearing a blue shirt and smiling. To begin to understand the bizarre electric current flowing through strange metals
The Anatomy of Electricity
The team’s goal was to dissect the BU Leads current in a strange metal. Did it come in electron-size chunks of charge. Did it come in chunks at all? To find out. They took inspiration from a classic way of measuring fluctuations. In a flow — the “shot noise” — a phenomenon that can be understood if we think of the ways that rain might fall during a rainstorm. Imagine you’re sitting in your car. And you know from a trustworthy weather forecast that 5 millimeters of rain will fall over the next hour.