5 November 2018

Quasi-2D to 3D Fermi surface topology change in Nd-doped CeCoIn5

De Haas-van Alphen measurements (left) agree with the calculated Fermi surfaces (right). Colors in the plot correspond to matching surface calculations. 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 Ce1-xNdxCoIn5 is due to a shape change in the Fermi surface. This finding ran counter to theoretical arguments and has led investigators in new directions.

THE TOOLS THEY USED

This research was conducted in the 35 Tesla, 32 mm Bore Resistive Magnet, 3He cryogenic system and 3He / 4He portable dilution refrigerator. at the DC Field Facility.

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:

  1. The appearance of the Q vector previously observed in neutron scattering measurements on Ce0.95Nd0.05CoIn5 is due to a transition from a two-dimensional to a three-dimensional metal.
  2. This transition results from the formation of a spin density wave<./li>
  3. 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

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.

Details

  • Research Area: Kondo/Heavy Fermion Systems, Superconductivity - Basic
  • Research Initiatives: Materials
  • Facility / Program: DC Field
  • Year: 2018
Last modified on 5 November 2018