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Title: Low-Temperature Charging Dynamics of the Ionic Liquid and Its Gating Effect on FeSe 0.5Te 0.5 Superconducting Films

Abstract

Ionic liquids (ILs) have been investigated extensively because of their unique ability to form the electric double layer (EDL), which induces high electrical field. For certain materials, low-temperature IL charging is needed to limit the electrochemical etching. Here, we report our investigation of the low-temperature charging dynamics in two widely used ILs—DEME-TF 2N and C4mim-TF 2N. Results show that the formation of the EDL at ~220 K requires several hours relative to milliseconds at room temperature, and an equivalent voltage V e is introduced as a measure of the EDL formation during the biasing process. Here, the experimental observation is supported by molecular dynamics simulation, which shows that the dynamics are logically a function of gate voltage, time, and temperature. To demonstrate the importance of understanding the charging dynamics, a 140 nm thick FeSe 0.5Te 0.5 film was biased using the DEME IL, showing a tunable T c between 18 and 35 K. Notably, this is the first observation of the tunability of the T c in thick film FeSe 0.5Te 0.5 superconductors.

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [2];  [3];  [3];  [4];  [5]; ORCiD logo [5]; ORCiD logo [6]; ORCiD logo [1]
  1. Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Huazhong Univ. of Science and Technology (HUST), Wuhan (China)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  4. Univ. of Tennessee, Knoxville, TN (United States)
  5. Brookhaven National Lab. (BNL), Upton, NY (United States)
  6. Huazhong Univ. of Science and Technology (HUST), Wuhan (China); Shenzhen Research Institute of Huazhong Univ. of Science and Technology, Shenzhen (China)
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1529071
Alternate Identifier(s):
OSTI ID: 1546498
Report Number(s):
BNL-211777-2019-JAAM
Journal ID: ISSN 1944-8244
Grant/Contract Number:  
SC0012704; AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
ACS Applied Materials and Interfaces
Additional Journal Information:
Journal Volume: 11; Journal Issue: 19; Journal ID: ISSN 1944-8244
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ionic liquid; molecular dynamics simulation; 2D materials; iron-based superconductor

Citation Formats

Zhang, Cheng, Zhao, Wei, Bi, Sheng, Rouleau, Christopher M., Fowlkes, Jason D., Boldman, Walker L., Gu, Genda, Li, Qiang, Feng, Guang, and Rack, Philip D. Low-Temperature Charging Dynamics of the Ionic Liquid and Its Gating Effect on FeSe0.5Te0.5 Superconducting Films. United States: N. p., 2019. Web. doi:10.1021/acsami.9b02373.
Zhang, Cheng, Zhao, Wei, Bi, Sheng, Rouleau, Christopher M., Fowlkes, Jason D., Boldman, Walker L., Gu, Genda, Li, Qiang, Feng, Guang, & Rack, Philip D. Low-Temperature Charging Dynamics of the Ionic Liquid and Its Gating Effect on FeSe0.5Te0.5 Superconducting Films. United States. doi:10.1021/acsami.9b02373.
Zhang, Cheng, Zhao, Wei, Bi, Sheng, Rouleau, Christopher M., Fowlkes, Jason D., Boldman, Walker L., Gu, Genda, Li, Qiang, Feng, Guang, and Rack, Philip D. Thu . "Low-Temperature Charging Dynamics of the Ionic Liquid and Its Gating Effect on FeSe0.5Te0.5 Superconducting Films". United States. doi:10.1021/acsami.9b02373. https://www.osti.gov/servlets/purl/1529071.
@article{osti_1529071,
title = {Low-Temperature Charging Dynamics of the Ionic Liquid and Its Gating Effect on FeSe0.5Te0.5 Superconducting Films},
author = {Zhang, Cheng and Zhao, Wei and Bi, Sheng and Rouleau, Christopher M. and Fowlkes, Jason D. and Boldman, Walker L. and Gu, Genda and Li, Qiang and Feng, Guang and Rack, Philip D.},
abstractNote = {Ionic liquids (ILs) have been investigated extensively because of their unique ability to form the electric double layer (EDL), which induces high electrical field. For certain materials, low-temperature IL charging is needed to limit the electrochemical etching. Here, we report our investigation of the low-temperature charging dynamics in two widely used ILs—DEME-TF2N and C4mim-TF2N. Results show that the formation of the EDL at ~220 K requires several hours relative to milliseconds at room temperature, and an equivalent voltage Ve is introduced as a measure of the EDL formation during the biasing process. Here, the experimental observation is supported by molecular dynamics simulation, which shows that the dynamics are logically a function of gate voltage, time, and temperature. To demonstrate the importance of understanding the charging dynamics, a 140 nm thick FeSe0.5Te0.5 film was biased using the DEME IL, showing a tunable Tc between 18 and 35 K. Notably, this is the first observation of the tunability of the Tc in thick film FeSe0.5Te0.5 superconductors.},
doi = {10.1021/acsami.9b02373},
journal = {ACS Applied Materials and Interfaces},
issn = {1944-8244},
number = 19,
volume = 11,
place = {United States},
year = {2019},
month = {4}
}

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