Probing Electrons in Novel Materials
For many scientists, solving the mystery of electron behaviour in novel materials and unleashing the potential for using these materials in a wide range of applications, are among the most exciting challenges of recent times. In certain materials, electrons collaborate to produce magnetism and superconductivity, states of matter whose properties have been harnessed in applications such as high-density storage using giant-magnetoresistance devices and magnetic resonance imaging using superconducting magnets.
As electron interactions get stronger, the possibility for unexpected behaviour and even new states of matter grows substantially. This is what interests Dr. Louis Taillefer, who is studying electron systems where unusual forms of magnetism or superconductivity are encountered. To do this, he cools materials down to extremely low temperatures and probes the electrons by subjecting them to strong magnetic fields and by making them transport heat or attenuate sound.
Over the past fifteen years, new materials have caused a number of revolutionary advances. A particularly dramatic surprise was the discovery of high-temperature superconductivity in a class of oxide materials known as cuprates. The mystery is how these materials can be transformed from an insulator to the best-known superconductor by removing some electrons. Cuprates seem to defy the theory of Fermi liquids - one of the cornerstones of condensed matter physics since the 1950s. More than 100,000 research papers have addressed the cuprate phenomenon, but no consensus has been achieved.
As recipient of a Canada Research Chair, Dr.Taillefer will investigate various classes of novel electronic materials. One of his major projects will concentrate on the behaviour of electrons in cuprates, asking among other questions if Fermi-liquid theory does indeed break down and, if so, how. His hope is that his research on the transport of heat at temperatures near absolute zero will provide new and stringent tests on proposed theories for the evolution from metal to superconductor to insulator.