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Title: Enhanced superconductivity in surface-electron-doped iron pnictide Ba(Fe1.94Co0.06)2As2

Abstract

The transition critical temperature (TC ) in a FeSe monolayer on SrTiO3 is enhanced up to 100 K. High TC is also found in bulk iron chalcogenides with similar electronic structure to that of monolayer FeSe, which suggests that higher TC may be achieved through electron doping, pushing the Fermi surface (FS) topology towards leaving only electron pockets. Such observation, however, has been limited to chalcogenides and is in contrast with the iron pnictides for which the maximum TC is achieved with both hole and electron pockets forming considerable FS nesting instability. Here, we report angle-resolved photoemission (ARPES) characterization revealing a monotonic increase of TC from 24 to 41.5 K upon surface doping on optimally doped Ba(Fe1-xCox)2As2 . The doping changes the overall FS topology towards that of chalcogenides through a rigid downward band shift. Our findings suggest that higher electron doping and concomitant changes in FS topology are favorable conditions for the superconductivity, not only for iron chalcogenides but also for iron pnictides.

Authors:
 [1];  [1];  [2];  [3];  [4];  [5];  [6]; ORCiD logo [6];  [3];  [7]
  1. Yonsei Univ., Seoul (Korea, Republic of); Inst. for Basic Science, Seoul (Korea, Republic of); Seoul National Univ. (Korea, Republic of)
  2. Pohang Univ. of Science and Technology (POSTECH) (Korea, Republic of)
  3. Inst. for Basic Science, Seoul (Korea, Republic of); Seoul National Univ. (Korea, Republic of)
  4. Osaka Univ. (Japan)
  5. National Inst. of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan)
  6. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS)
  7. Inst. for Basic Science, Seoul (Korea, Republic of); Seoul National Univ. (Korea, Republic of); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS); Korea Advanced Inst. Science and Technology (KAIST), Daejeon (Korea, Republic of)
Publication Date:
Research Org.:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1436609
Grant/Contract Number:  
AC02-05CH11231
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Nature Materials
Additional Journal Information:
Journal Volume: 15; Journal Issue: 12; Journal ID: ISSN 1476-1122
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Kyung, W. S., Huh, S. S., Koh, Y. Y., Choi, K. -Y., Nakajima, M., Eisaki, H., Denlinger, J. D., Mo, S. -K., Kim, C., and Kim, Y. K. Enhanced superconductivity in surface-electron-doped iron pnictide Ba(Fe1.94Co0.06)2As2. United States: N. p., 2016. Web. doi:10.1038/nmat4728.
Kyung, W. S., Huh, S. S., Koh, Y. Y., Choi, K. -Y., Nakajima, M., Eisaki, H., Denlinger, J. D., Mo, S. -K., Kim, C., & Kim, Y. K. Enhanced superconductivity in surface-electron-doped iron pnictide Ba(Fe1.94Co0.06)2As2. United States. https://doi.org/10.1038/nmat4728
Kyung, W. S., Huh, S. S., Koh, Y. Y., Choi, K. -Y., Nakajima, M., Eisaki, H., Denlinger, J. D., Mo, S. -K., Kim, C., and Kim, Y. K. 2016. "Enhanced superconductivity in surface-electron-doped iron pnictide Ba(Fe1.94Co0.06)2As2". United States. https://doi.org/10.1038/nmat4728. https://www.osti.gov/servlets/purl/1436609.
@article{osti_1436609,
title = {Enhanced superconductivity in surface-electron-doped iron pnictide Ba(Fe1.94Co0.06)2As2},
author = {Kyung, W. S. and Huh, S. S. and Koh, Y. Y. and Choi, K. -Y. and Nakajima, M. and Eisaki, H. and Denlinger, J. D. and Mo, S. -K. and Kim, C. and Kim, Y. K.},
abstractNote = {The transition critical temperature (TC ) in a FeSe monolayer on SrTiO3 is enhanced up to 100 K. High TC is also found in bulk iron chalcogenides with similar electronic structure to that of monolayer FeSe, which suggests that higher TC may be achieved through electron doping, pushing the Fermi surface (FS) topology towards leaving only electron pockets. Such observation, however, has been limited to chalcogenides and is in contrast with the iron pnictides for which the maximum TC is achieved with both hole and electron pockets forming considerable FS nesting instability. Here, we report angle-resolved photoemission (ARPES) characterization revealing a monotonic increase of TC from 24 to 41.5 K upon surface doping on optimally doped Ba(Fe1-xCox)2As2 . The doping changes the overall FS topology towards that of chalcogenides through a rigid downward band shift. Our findings suggest that higher electron doping and concomitant changes in FS topology are favorable conditions for the superconductivity, not only for iron chalcogenides but also for iron pnictides.},
doi = {10.1038/nmat4728},
url = {https://www.osti.gov/biblio/1436609}, journal = {Nature Materials},
issn = {1476-1122},
number = 12,
volume = 15,
place = {United States},
year = {Mon Aug 15 00:00:00 EDT 2016},
month = {Mon Aug 15 00:00:00 EDT 2016}
}

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Cited by: 16 works
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Works referenced in this record:

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Effect of Structural Parameters on Superconductivity in Fluorine-Free LnFeAsO 1- y (Ln = La, Nd)
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Superconductivity and Crystal Structures of (Ba1-xKx)Fe2As2 (x = 0 - 1)
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High-temperature superconductivity in iron-based materials
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Works referencing / citing this record:

Origin of charge transfer and enhanced electron–phonon coupling in single unit-cell FeSe films on SrTiO3
journal, August 2017


Enhanced superconductivity of Ba 0.5 K 0.5 Fe 2 As 2 under surface potassium dosing
journal, October 2018