Quasi-2D to 3D Fermi Surface Topology Change in Nd-Doped CeCoIn5

Published November 05, 2018

De Haas-van Alphen measurements (left) agree with the calculated Fermi surfaces (right). Colors in the plot correspond to matching surface calculations.

Scientists found that the emergence of an exotic quantum mechanical phase in Ce_1-xNd_xCoIn₅ is due to a shape change in the Fermi surface. This finding ran counter to theoretical arguments and has led investigators in new directions.

What did scientists discover?

The experiment, which combined high magnetic fields with temperatures close to absolute zero, produced three key findings on the very unusual "Q-phase" in neodymium-doped CeCoIn⁵, in which magnetism and superconductivity coexist:

The appearance of the Q vector previously observed in neutron scattering measurements on Ce_0.95Nd_0.05CoIn₅ is due to a transition from a two-dimensional to a three-dimensional metal.
This transition results from the formation of a spin density wave
Neodymium likely alters the electronic pairing potential that leads to the superconductivity.

Why is this important?

Physicists seek to better understand exotic quantum mechanical states in unusual superconductors, such as the Q-phase. These results show an increase from two- to three-dimensionality. This argues against previously proposed Fermi surface nesting and points instead to spin density wave formation as the driving force for the transition.

Who did the research?

J. Klotz,^1,2 K. Götze,^1,2 I. Sheikin,³ T. Förster,¹ D. Graf,⁴ J.-H. Park,⁴ E. S. Choi,⁴ R. Hu,⁵ C. Petrovic,⁵ J. Wosnitza,^1,2 and E. L. Green¹

¹HZDR, Germany; ²TU Dresden, Germany; ³LNCMI, France ; ⁴National MagLab, FSU ; ⁵Brookhaven National Lab

Why did they need the MagLab?

The combination of high magnetic fields and low temperatures offered at the MagLab was crucial to resolving the many high-frequency oscillations present in these heavy fermion compounds.

Details for scientists

View or download the expert-level Science Highlight, Quasi-2D to 3D Fermi Surface Topology Change in Ce_1-xNd_xCoIn₅
Read the full-length publication, Fermi surface reconstruction and dimensional topology change in Nd-doped CeCoIn₅, in Phys. Rev. B Rapid Commun.

Funding

This research was funded by the following grants: G.S. Boebinger (NSF DMR-1157490); BNL (U.S. DOE No. DE-SC0012704), C. Petrovic (Humboldt Foundation); I. Sheikin, J. Wosnitza (ANR-DFG Grant Fermi-NESt); J. Wosnitza (GRK 1621)

For more information, contact Tim Murphy.