skip to main content

Title: Theory of point contact spectroscopy in correlated materials

Here, we developed a microscopic theory for the point-contact conductance between a metallic electrode and a strongly correlated material using the nonequilibrium Schwinger-Kadanoff-Baym-Keldysh formalism. We explicitly show that, in the classical limit, contact size shorter than the scattering length of the system, the microscopic model can be reduced to an effective model with transfer matrix elements that conserve in-plane momentum. We found that the conductance dI/dV is proportional to the effective density of states, that is, the integrated single-particle spectral function A(ω = eV) over the whole Brillouin zone. From this conclusion, we are able to establish the conditions under which a non-Fermi liquid metal exhibits a zero-bias peak in the conductance. Lastly, this finding is discussed in the context of recent point-contact spectroscopy on the iron pnictides and chalcogenides, which has exhibited a zero-bias conductance peak.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1]
  1. Univ. of Illinois, Urbana, IL (United States). Dept. of Physics
Publication Date:
OSTI Identifier:
1235102
Grant/Contract Number:
AC02-98CH10886; 12-06766; AC0298CH1088; NSF DMR 12-06766
Type:
Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 112; Journal Issue: 3; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Research Org:
Energy Frontier Research Centers (EFRC). Center for Emergent Superconductivity (CES)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF)
Contributing Orgs:
CES partners with Brookhaven National Laboratory (BNL); Argonne National Laboratory; University of Illinois, Urbana-Champaign; Los Alamos National Laboratory
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; phonons; thermal conductivity; energy storage (including batteries and capacitors); superconductivity; defects; spin dynamics; non-Fermi liquid; electronic nematicity; iron-based superconductors