Scientists find 'knob' to control magnetic behavior in quantum material
Magnetism, one of the oldest technologies known to humans, is at the forefront of new-age materials that could enable next-generation lossless electronics and quantum computers. Researchers led by Penn State and the university of California, San Diego have discovered a new ‘knob’ to control the magnetic behavior of one promising quantum material, and the findings could pave the way toward novel, efficient and ultra-fast devices.
“The unique quantum mechanical make-up of this material — manganese bismuth telluride — allows it to carry lossless electrical currents, something of tremendous technological interest,” said Hari Padmanabhan, who led the research as a graduate student at Penn State. “What makes this material especially intriguing is that this behavior is deeply connected to its magnetic properties. So, a knob to control magnetism in this material could also efficiently control these lossless currents.”
Manganese bismuth telluride, a 2D material made of atomically thin stacked layers, is an example of a topological insulator, exotic materials that simultaneously can be insulators and conductors of electricity, the scientists said. Importantly, because this material is also magnetic, the currents conducted around its edges could be lossless, meaning they do not lose energy in the form of heat. Finding a way to tune the weak magnetic bonds between the layers of the material could unlock these functions.
Tiny vibrations of atoms, or phonons, in the material may be one way to achieve this, the scientists reported April 8 in the journal Nature Communications.
“Phonons are tiny atomic wiggles — atoms dancing together in various patterns, present in all materials,” Padmanabhan said. “We show that these atomic wiggles can potentially function as a knob to tune the magnetic bonding between the atomic layers in manganese bismuth telluride.”
The scientists at Penn State studied the material using a technique called magneto-optical spectroscopy — shooting a laser onto a sample of the material and measuring the color and intensity of the reflected light, which carries information on the atomic vibrations. The team observed how the vibrations changed as they altered the temperature and magnetic field. More