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Title: Stabilization of s -wave superconductivity through arsenic p -orbital hybridization in electron-doped BaFe 2 As 2

In this paper, using random-phase approximation spin-fluctuation theory, we study the influence of the hybridization between iron $d$ orbitals and pnictide $p$ orbitals on the superconducting pairing state in iron-based superconductors. The calculations are performed for a 16-orbital Hubbard-Hund tight-binding model of $${\mathrm{BaFe}}_{2}{\mathrm{As}}_{2}$$ that includes the As-$p$ orbital degrees of freedom in addition to the Fe-$d$ orbitals and compared to calculations for a 10-orbital Fe-$d$ only model. In both models we find a leading $${s}^{±{}}$$ pairing state and a subleading $${d}_{{x}^{2}{-}{y}^{2}}$$-wave state in the parent compound. Upon doping, we find that the $${s}^{±{}}$$ state remains the leading state in the 16-orbital model up to a doping level of 0.475 electrons per unit cell, at which the hole Fermi-surface pockets at the zone center start to disappear. This is in contrast to the 10-orbital model, where the $d$-wave state becomes the leading state at a doping of less than 0.2 electrons. This improved stability of $${s}^{±{}}$$ pairing is found to arise from a decrease of $${d}_{xy}$$ orbital weight on the electron pockets due to hybridization with the As-$p$ orbitals and the resulting reduction of near $$({\pi},{\pi})$$ spin-fluctuation scattering which favors the competing $d$-wave state. Finally, these results show that the orbital dependent hybridization of Fermi-surface Bloch states with the usually neglected $p$-orbital states is an important ingredient in an improved itinerant pairing theory.
Authors:
 [1] ;  [2] ;  [2]
  1. Rice Univ., Houston, TX (United States). Dept. of Physics and Astronomy
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences. Computational Sciences and Engineering Division
Publication Date:
Grant/Contract Number:
AC05-00OR22725; DMR-1308603
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 98; Journal Issue: 2; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Rice Univ., Houston, TX (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Fermi surface; pairing mechanisms; spin fluctuations; superconductivity; pnictides; random phase approximation; tight-binding model
OSTI Identifier:
1468135
Alternate Identifier(s):
OSTI ID: 1460020

Tam, David W., Berlijn, Tom, and Maier, Thomas A.. Stabilization of s -wave superconductivity through arsenic p -orbital hybridization in electron-doped BaFe2As2. United States: N. p., Web. doi:10.1103/PhysRevB.98.024507.
Tam, David W., Berlijn, Tom, & Maier, Thomas A.. Stabilization of s -wave superconductivity through arsenic p -orbital hybridization in electron-doped BaFe2As2. United States. doi:10.1103/PhysRevB.98.024507.
Tam, David W., Berlijn, Tom, and Maier, Thomas A.. 2018. "Stabilization of s -wave superconductivity through arsenic p -orbital hybridization in electron-doped BaFe2As2". United States. doi:10.1103/PhysRevB.98.024507.
@article{osti_1468135,
title = {Stabilization of s -wave superconductivity through arsenic p -orbital hybridization in electron-doped BaFe2As2},
author = {Tam, David W. and Berlijn, Tom and Maier, Thomas A.},
abstractNote = {In this paper, using random-phase approximation spin-fluctuation theory, we study the influence of the hybridization between iron $d$ orbitals and pnictide $p$ orbitals on the superconducting pairing state in iron-based superconductors. The calculations are performed for a 16-orbital Hubbard-Hund tight-binding model of ${\mathrm{BaFe}}_{2}{\mathrm{As}}_{2}$ that includes the As-$p$ orbital degrees of freedom in addition to the Fe-$d$ orbitals and compared to calculations for a 10-orbital Fe-$d$ only model. In both models we find a leading ${s}^{±{}}$ pairing state and a subleading ${d}_{{x}^{2}{-}{y}^{2}}$-wave state in the parent compound. Upon doping, we find that the ${s}^{±{}}$ state remains the leading state in the 16-orbital model up to a doping level of 0.475 electrons per unit cell, at which the hole Fermi-surface pockets at the zone center start to disappear. This is in contrast to the 10-orbital model, where the $d$-wave state becomes the leading state at a doping of less than 0.2 electrons. This improved stability of ${s}^{±{}}$ pairing is found to arise from a decrease of ${d}_{xy}$ orbital weight on the electron pockets due to hybridization with the As-$p$ orbitals and the resulting reduction of near $({\pi},{\pi})$ spin-fluctuation scattering which favors the competing $d$-wave state. Finally, these results show that the orbital dependent hybridization of Fermi-surface Bloch states with the usually neglected $p$-orbital states is an important ingredient in an improved itinerant pairing theory.},
doi = {10.1103/PhysRevB.98.024507},
journal = {Physical Review B},
number = 2,
volume = 98,
place = {United States},
year = {2018},
month = {7}
}