Title : Atomic Semiconductor via flat phonon bands
Date / Time : 20 Sep, 2022 / 5:00 P.M
Speaker : Jun Hee Lee(UNIST)
Abstract : Flat energy bands in momentum space generate localized states and cause unusual phenomena such as graphene superconductivity in electrons. However flat bands in phonon were not discovered yet. For the first time, we discovered flat bands in phonon exist in a ferroelectric HfO2 [1] and produce a localized motion of atoms as if their chemical bond temporarily disappears by an external voltage. With the vanishing bond, each atom can be freely displaced by the voltage for information storage. Our discovery of the atom control directly in solid will lead us to the design of densest memory semiconductors up to ~100 TB. As Einstein’s relativity (E=mc2) enabled us to make bombs out of atoms not out of materials, with our “Atomic Semiconductor” we will design semiconductors on an atomic scale rather than a materials scale for a data center in your hand.
References
[1] “Scale-free ferroelectricity driven by flat phonon bands in HfO2”, H.-J. Lee et al., Science 369, 1343 (2020).