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Title: Lattice dynamics of ultrathin FeSe films on SrTiO 3

Charge transfer and electron-phonon coupling (EPC) are proposed to be two important constituents associated with enhanced superconductivity in the single unit cell FeSe films on oxide surfaces. Using high-resolution electron energy loss spectroscopy combined with first-principles calculations, we have explored here the lattice dynamics of ultrathin FeSe films grown on $${\mathrm{SrTiO}}_{3}$$. We show that, despite the significant effect from the substrate on the electronic structure and superconductivity of the system, the FeSe phonons in the films are unaffected. The energy dispersion and linewidth associated with the Fe- and Se-derived vibrational modes are thickness and temperature independent. Theoretical calculations indicate the crucial role of antiferromagnetic correlation in FeSe to reproduce the experimental phonon dispersion. Importantly, the only detectable change due to the growth of FeSe films is the broadening of the Fuchs-Kliewer (F-K) phonons associated with the lattice vibrations of $${\mathrm{SrTiO}}_{3}$$(001) substrate. Finally, if EPC plays any role in the enhancement of film superconductivity, it must be the interfacial coupling between the electrons in FeSe film and the F-K phonons from substrate rather than the phonons of FeSe.
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [2] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [4] ;  [4] ;  [4] ;  [5] ;  [5] ;  [1] ;  [6]
  1. Chinese Academy of Sciences (CAS), Beijing (China). Beijing National Lab. for Condensed Matter Physics. Inst. of Physics; Univ. of Chinese Academy of Sciences, Beijing (China). School of Physical Sciences
  2. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Physics and Astronomy
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences. Computational Sciences and Engineering Division
  4. Chinese Academy of Sciences (CAS), Beijing (China). Beijing National Lab. for Condensed Matter Physics. Inst. of Physics
  5. Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Physics and Astronomy
  6. Chinese Academy of Sciences (CAS), Beijing (China). Beijing National Lab. for Condensed Matter Physics. Inst. of Physics; Univ. of Chinese Academy of Sciences, Beijing (China). School of Physical Sciences; Collaborative Innovation Center of Quantum Matter, Beijing (China)
Publication Date:
Grant/Contract Number:
AC05-00OR22725; AC02-05CH11231; DMR 1608865; 11634016; 2017YFA0303600
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 97; Journal Issue: 3; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States); Louisiana State Univ., Baton Rouge, LA (United States); Chinese Academy of Sciences (CAS), Beijing (China); Univ. of Chinese Academy of Sciences, Beijing (China)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF); National Natural Science Foundation of China (NNSFC); National Key R&D Program of China; Youth Innovation Promotion Association of Chinese Academy of Sciences (CAS)
Country of Publication:
United States
Language:
English
Subject:
electron-phonon coupling; lattice dynamics; optical phonons; phonons; surface & interfacial phenomena; interfaces; superconductors; ab initio calculations; high-resolution electron energy loss spectroscopy
OSTI Identifier:
1484097
Alternate Identifier(s):
OSTI ID: 1416071

Zhang, Shuyuan, Guan, Jiaqi, Wang, Yan, Berlijn, Tom, Johnston, Steve, Jia, Xun, Liu, Bing, Zhu, Qing, An, Qichang, Xue, Siwei, Cao, Yanwei, Yang, Fang, Wang, Weihua, Zhang, Jiandi, Plummer, E. W., Zhu, Xuetao, and Guo, Jiandong. Lattice dynamics of ultrathin FeSe films on SrTiO3. United States: N. p., Web. doi:10.1103/PhysRevB.97.035408.
Zhang, Shuyuan, Guan, Jiaqi, Wang, Yan, Berlijn, Tom, Johnston, Steve, Jia, Xun, Liu, Bing, Zhu, Qing, An, Qichang, Xue, Siwei, Cao, Yanwei, Yang, Fang, Wang, Weihua, Zhang, Jiandi, Plummer, E. W., Zhu, Xuetao, & Guo, Jiandong. Lattice dynamics of ultrathin FeSe films on SrTiO3. United States. doi:10.1103/PhysRevB.97.035408.
Zhang, Shuyuan, Guan, Jiaqi, Wang, Yan, Berlijn, Tom, Johnston, Steve, Jia, Xun, Liu, Bing, Zhu, Qing, An, Qichang, Xue, Siwei, Cao, Yanwei, Yang, Fang, Wang, Weihua, Zhang, Jiandi, Plummer, E. W., Zhu, Xuetao, and Guo, Jiandong. 2018. "Lattice dynamics of ultrathin FeSe films on SrTiO3". United States. doi:10.1103/PhysRevB.97.035408.
@article{osti_1484097,
title = {Lattice dynamics of ultrathin FeSe films on SrTiO3},
author = {Zhang, Shuyuan and Guan, Jiaqi and Wang, Yan and Berlijn, Tom and Johnston, Steve and Jia, Xun and Liu, Bing and Zhu, Qing and An, Qichang and Xue, Siwei and Cao, Yanwei and Yang, Fang and Wang, Weihua and Zhang, Jiandi and Plummer, E. W. and Zhu, Xuetao and Guo, Jiandong},
abstractNote = {Charge transfer and electron-phonon coupling (EPC) are proposed to be two important constituents associated with enhanced superconductivity in the single unit cell FeSe films on oxide surfaces. Using high-resolution electron energy loss spectroscopy combined with first-principles calculations, we have explored here the lattice dynamics of ultrathin FeSe films grown on ${\mathrm{SrTiO}}_{3}$. We show that, despite the significant effect from the substrate on the electronic structure and superconductivity of the system, the FeSe phonons in the films are unaffected. The energy dispersion and linewidth associated with the Fe- and Se-derived vibrational modes are thickness and temperature independent. Theoretical calculations indicate the crucial role of antiferromagnetic correlation in FeSe to reproduce the experimental phonon dispersion. Importantly, the only detectable change due to the growth of FeSe films is the broadening of the Fuchs-Kliewer (F-K) phonons associated with the lattice vibrations of ${\mathrm{SrTiO}}_{3}$(001) substrate. Finally, if EPC plays any role in the enhancement of film superconductivity, it must be the interfacial coupling between the electrons in FeSe film and the F-K phonons from substrate rather than the phonons of FeSe.},
doi = {10.1103/PhysRevB.97.035408},
journal = {Physical Review B},
number = 3,
volume = 97,
place = {United States},
year = {2018},
month = {1}
}

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