Specific heat in strongly hole-doped iron-based superconductors
Journal Article
·
· Physical Review. B
- Univ. of Minnesota, Minneapolis, MN (United States); DOE/OSTI
- Univ. of Minnesota, Minneapolis, MN (United States)
We compute specific heat C(T) in a strongly hole-doped Fe-based superconductor, like KFe2As2, which has only hole pockets. We model the electronic structure by a three-orbital/three-pocket model with two smaller hole pockets made out of dxz and dyz orbitals and a larger pocket made out of dxy orbital. We use as an input the experimental fact that the mass of dxy fermion is several times heavier than that of dxz/dyz fermions. We argue that the heavy dxy band gives the largest contribution to the specific heat in the normal state, but the superconducting gap on the dxy pocket is much smaller than that on dxz/dyz pockets. We argue that in this situation the jump of C(T) at Tc is determined by dxz/dyz fermions, and the ratio (Cs–Cn)/Cn is a fraction of that in a one-band BCS superconductor. At T < Tc,C(T) remains relatively flat down to some T*, below which it rapidly drops. This behavior is consistent with the data for KFe2As2 and related materials. We use one-parameter model for the interactions and fix this only parameter by matching the experimental ratio of the gaps on the two dxz/dyz pockets. Furthermore, we argue that the resulting parameter-free model reproduces quantitatively the data on C(T) for KFe2As2. We further argue that the very existence of a finite T* < Tc favors s+– gap structure over d-wave, because in the latter case T* would almost vanish.
- Research Organization:
- Univ. of Minnesota, Minneapolis, MN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC0014402
- OSTI ID:
- 1612172
- Alternate ID(s):
- OSTI ID: 1491618
- Journal Information:
- Physical Review. B, Journal Name: Physical Review. B Journal Issue: 2 Vol. 99; ISSN 2469-9950
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Competing instabilities, orbital ordering, and splitting of band degeneracies from a parquet renormalization group analysis of a four-pocket model for iron-based superconductors: Application to FeSe
Displacement and annihilation of Dirac gap nodes in d-wave iron-based superconductors
Specific heat and gap structure of a nematic superconductor: Application to FeSe
Journal Article
·
Sun Feb 05 19:00:00 EST 2017
· Physical Review. B
·
OSTI ID:1535859
Displacement and annihilation of Dirac gap nodes in d-wave iron-based superconductors
Journal Article
·
Sun Nov 27 19:00:00 EST 2016
· Physical Review. B
·
OSTI ID:1535787
Specific heat and gap structure of a nematic superconductor: Application to FeSe
Journal Article
·
Sun Sep 26 20:00:00 EDT 2021
· Physical Review. B
·
OSTI ID:1851913