Pnictides Our current work on pnictides is focused on the class of diantimonides that include: LaSb2 CeSb2 DySb2 This work includes angle-resolved photoemission studies at CAMD, STM measurements, and neutron diffractions measurements conducted with Jim Richardson at the Argonne IPNS. Our most recent trip to IPNS to do neutron scattering measurements on LaSb2 and CeSb2 is here. For more information on these studies check out the listings in the publications link.

LaSb2 exhibits a highly linear magnetoresistance despite the fact that it consists purely of non-magnetic elements. The figure to the right comes from "High magnetic field sensor using LaSb2," D. P. Young, R. G. Goodrich, D. F. DiTusa, S. Guo, P. W. Adams, J. Y. Chan, and D. Hall, Appl. Phys. Lett. 82, 3173 (2003).

The orthorhombic crystal structure of LaSb2 is highly layered. Its space group is 64 cmca with a=6.319 b=6.173 and c=18.57 Angstroms. The atoms are located at: La 1 - 0 0.3653 0.3902 Sb 1 - 0 0.8686 0.4360 Sb 2 - 0 0.1222 0.25

The electronic structure of LaSb2 is highly two dimensional and the Fermi surface shows a remarkable degree of nesting. This nesting may be responsible for charge density waves at low temperature. In turn, the CDW's may be responsible for the magnetoresistance.

Band Structure

Currently the issue of why there is a linear magnetoresistance is unresolved. Clearly there is a very interesting Fermi surface that suggests that strong nesting may give rise to exotic behavior. Furthermore, the bands look similar to those that Abrikosov postulated may lead to a linear MR yet the linear response to VERY low fields, and the high carrier density in our single crystals seem to rule out Abrikosov's mechanism.