10 October 2017

Selective mass enhancement close to a quantum critical point

Temperature dependence of the upper critical field in thin films with various doping levels, for magnetic fields applied along the crystallographic c-axis. Lines are fits to a two-band WHH model. Temperature dependence of the upper critical field in thin films with various doping levels, for magnetic fields applied along the crystallographic c-axis. Lines are fits to a two-band WHH model.

This finding sheds light on the role of quasiparticle mass enhancement near a quantum critical point in one of the leading families of high-temperature superconductors.

What did scientists discover?

The mass of the electric charge carriers is found to be enhanced in BaFe2(As1-xPx)2 near the same concentration Xc ~ 0.3 where high-temperature superconductivity is strongest. This experiment is unique in that it finds that mass enhancement occurs only for some of the electric charge carriers. By measuring the magnetic field required to suppress superconductivity, the experiment reveals two classes of charge carriers: the charge carrier mass is enhanced near X = 0.3 in one class but not in the other, which shows little change with X.

Why is this important?

This finding helps us understand the role of quasiparticle mass enhancement near a quantum critical point in one of the leading families of high-temperature superconductors.

Who did the research?

V. Grinenko1,2,3, K. Iida2,3, F. Kurth1,2, D.V. Efremov2, S.-L. Drechsler2, I. Cherniavskii4, I. Morozov 2,4, J. Hänish 2,5, T. Förster6, C. Tarantini7, J. Jaroszynski7, B. Maiorov8, M. Jaime8, A. Yamamoto9, I. Nakamura3, H. Ikuta3 & R. Hühne 2

1TU Dresden, GE; 2IFW Dresden, GE X; 3Nagoya Univ, JP; 4Lomonosov MSU, Russ. Fed.; 5KIT, Karlsruhe, GE; 6HLD-EMFL, Dresden, GE; 7National MagLab, Florida, USA; 8LANL, NM, USA; 9Tokyo Univ. A&T, Tokyo, JP.

Why did they need the MagLab?

The robustness of superconductivity in BaFe2(As1-xPx)2 requires magnetic fields in excess of 60T to study the temperature dependence of the upper critical field Hc2(T).

THE TOOLS THEY USED

This research was conducted in the 65 Tesla Multi-Shot Magnet at the MagLab's Pulsed Field Facility and the 35 Tesla, 32 mm Bore Magnet at the DC Field Facility.

Details for scientists

Funding

This research was funded by the following grants: G.S. Boebinger (NSF DMR-1157490); V. Grinenko (DFG-GR 4667/1-1)


For more information, contact Marcelo Jaime.

Details

  • Research Area: Superconductivity - Basic
  • Research Initiatives: Energy,Materials
  • Facility / Program: DC Field, Pulsed Field
  • Year: 2017
Last modified on 12 October 2017