Just as magnetic materials have opposing North and South poles, ferroelectric materials have opposing positive charges and negative charges that exhibit measurable differences in electric potential. MIT Researchers recently demonstrated this ferroelectric behavior along the edges of atomically thin tin-tellurium film at room temperature.
Measurements showed the energy gap, or bandgap, of this ultra-thin (2-D) film to be about eight times higher than the bandgap in bulk (3-D) tin-tellurium, with an on/off ratio as high as 3,000
Their findings hold promise for making random access memory (RAM) devices from this special semiconductor material, which is known as a topological crystalline insulator.
This discovery is very exciting because usually when you decrease the thickness from the 3-D to 2-D, the phase transition temperature always decreases and therefore could destroy the ferroelectricity. But in this case, the [ferroelectric] phase transition temperature increased. It’s quite unusual.
The next step will be to show these results in actual devices. Future challenges include how to easily and inexpensively produce high quality tin-tellurium thin films and how to precisely control the polarization direction.
