Intrinsic electronic inhomogeneities as seen by resonance techniques: NMR in iron pnictides

Date

Dec 4, 2015

Time

10:30 AM - 11:30 AM

Speaker

Dr. Guillaume Lang

Affiliation

ESPC, Paris Institute of Technology, CNRS

Language

en

Main Topic

Materialien

Other Topics

Materialien, Physik

Host

Christine Malbrich

Description

Abstract The phase diagrams of correlated-electron materials often feature original electronic states, whose possible interplay is thought to be a key question. Such is the case for iron-based superconductors, which develop unconventional superconductivity when doping a magnetically-ordered parent compound. This proximity of the two ground states has led to a large body of work investigating ground-state competition and coexistence, and whether electronic nematicity and orbital/spin fluctuations already play a role in the paramagnetic state. However, complications arise from: (i) Defining the extent of coexistence (length scale, volume fraction, existence criteria) (ii) Taking into account electronic inhomogeneities intrinsic to the paramagnetic state. I will first give an introduction on how resonance techniques such as NMR/muSR/ESR can infer the presence of the nanoscale coexistence of electronic states. Then, I will show how the competition of static magnetism and superconductivity in 1111 iron pnictides is spatial in character, originating from two types of nanometric regions which seem to arise from an above room- temperature phase transition.

Links

• Seminars at the IFW

Last modified: Dec 4, 2015, 9:00:05 AM