“It sounds strange, but basically we can change the dimensionality of this world to a two-dimensional, pre-Aristotle world,” said Andrei Lebed of the University of Arizona. (The ancient Greek philosopher Artistotle first reasoned that the Earth was not flat, but curved.) “We can confine electrons to just one plane, two dimensions in space, by applying the magnetic field.”
Conventional wisdom says that superconductivity is destroyed at high currents, which are produced in strong magnetic fields, because as current increases, superconductors work only at progressively lower temperatures. Lebed has discovered this isn’t the case in two-dimensions.
“My work may definitely led to superconductivity that survives at ultra-strong magnetic fields because superconductivity is not destroyed by currents in the two-dimensional world. Two-dimensional superconductivity will be stable at extremely high currents and magnetic fields. This work explores new nano-scale properties of solids in a magnetic field,” he said.
Lebed and colleagues Michael Naughton of Boston College and Heon-Ick Ha of Harvard University published two Physical Review Letters articles in 2003 and 2004 that showed that it is theoretically and experimentally possible to use magnetism to create “standing waves” of electrons within organic (carbon-containing) crystals. The phenomenon has to do with quantum mechanical wave properties of electrons that interfere with, or cancel, waves that would otherwise propagate in three dimensions in Earth’s normal, much weaker, magnetic field.
In research published in the December 9 issue of Physical Review Letters, Lebed explains that it is also theoretically possible to restrict standing electron waves to a single molecule. Electron standing waves that occupy about 20 atomic layers within a weak magnetic field can be localized to a single atomic layer in strong — but experimentally attainable — magnetic fields.
Electrons will become completely two-dimensional within laboratory-produced magnetic fields that are between 200,000 times and a million times stronger than the magnetic field at the surface of the Earth, Lebed said. “These strong fields are still a hundred to a thousand times weaker that the magnetic fields in the atoms, and that’s a key point,” he added.
“I am delighted because I found that you will not destroy the atoms and molecules in the conducting material, but just qualitatively change the properties of the valence conduction electrons,” Lebed said. (A valence electron is an electron in an outer shell of an atom that can form chemical bonds with other atoms.) “Basically, we can change the chemistry of the solids by how we rotate the sample in the magnetic field,” he added.
“The results are not restricted to organic materials, but should be applicable to the important class of high-temperature superconductors.”
Adapted from a University of Arizona Press Release