New Fe-based superconductors
In February the 1st report of a high-Tc
superconductor based on Fe appeared; Tc
is now as high as 53K.
With Cheng group, we found
band structure
for LOFA material, predicting AF
order
which was later observed. We also proposed a method to determine
the SC order parameter symmetry. Left: ab initio Fermi
surface and dxy state.
BSCCO supermodulation
The high-Tc materials family BSCCO exhibits a structural
supermodulation which has been recently found to correlate with the
local energy gap. Here is the result of the
first density
functional theory calculation of such a structural supermodulation,
with Hai-Ping Cheng's group, showing theory (right top) and x-ray determined
atomic positions (right bottom).
Disorder-induced magnetism Impurities induce magnetic droplets in strongly correlated systems (see arXiv:0711.0877). Left: magnetization of a Hubbard model with d-wave pairing in the presence of impurities. Inset: density of states is suppressed as Hubbard U is increased
[PRL 99, 147002 (2007)]. Implications for NMR are discussed in PRB 75, 054520 (2007).
