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Title: Dirac surface state–modulated spin dynamics in a ferrimagnetic insulator at room temperature

Abstract

This work demonstrates markedly modified spin dynamics of magnetic insulator (MI) by the spin momentum–locked Dirac surface states of the adjacent topological insulator (TI), which can be harnessed for spintronic applications. As the Bi concentration x is systematically tuned in 5-nm-thick (Bi xSb 1-x) 2Te 3 TI films, the weight of the surface relative to bulk states peaks at x = 0.32 when the chemical potential approaches the Dirac point. At this concentration, the Gilbert damping constant of the precessing magnetization in 10-nm-thick Y 3Fe 5O 12 MI films in the MI/TI heterostructures is enhanced by an order of magnitude, the largest among all concentrations. In addition, the MI acquires additional strong magnetic anisotropy that favors the in-plane orientation with similar Bi concentration dependence. These extraordinary effects of the Dirac surface states distinguish TI from other materials such as heavy metals in modulating spin dynamics of the neighboring magnetic layer.

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3]; ORCiD logo [1]; ORCiD logo [4]; ORCiD logo [5];  [1]; ORCiD logo [2];  [2];  [6];  [7]; ORCiD logo [2];  [1]
  1. Univ. of California, Riverside, CA (United States)
  2. Peking Univ., Beijing (China); Collaborative Innovation Center of Quantum Matter, Beijing (China)
  3. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Pennsylvania State Univ., University Park, PA (United States)
  4. Advanced Science Research Center, Japan Atomic Energy Agency, Tokai (Japan)
  5. Advanced Science Research Center, Japan Atomic Energy Agency, Tokai (Japan); Tohoku University, Sendai (Japan)
  6. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  7. Pennsylvania State Univ., University Park, PA (United States)
Publication Date:
Research Org.:
Univ. of California, Riverside, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1499918
Grant/Contract Number:  
SC0012670
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Science Advances
Additional Journal Information:
Journal Volume: 4; Journal Issue: 6; Journal ID: ISSN 2375-2548
Publisher:
AAAS
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE

Citation Formats

Tang, Chi, Song, Qi, Chang, Cui-Zu, Xu, Yadong, Ohnuma, Yuichi, Matsuo, Mamoru, Liu, Yawen, Yuan, Wei, Yao, Yunyan, Moodera, Jagadeesh S., Maekawa, Sadamichi, Han, Wei, and Shi, Jing. Dirac surface state–modulated spin dynamics in a ferrimagnetic insulator at room temperature. United States: N. p., 2018. Web. doi:10.1126/sciadv.aas8660.
Tang, Chi, Song, Qi, Chang, Cui-Zu, Xu, Yadong, Ohnuma, Yuichi, Matsuo, Mamoru, Liu, Yawen, Yuan, Wei, Yao, Yunyan, Moodera, Jagadeesh S., Maekawa, Sadamichi, Han, Wei, & Shi, Jing. Dirac surface state–modulated spin dynamics in a ferrimagnetic insulator at room temperature. United States. doi:10.1126/sciadv.aas8660.
Tang, Chi, Song, Qi, Chang, Cui-Zu, Xu, Yadong, Ohnuma, Yuichi, Matsuo, Mamoru, Liu, Yawen, Yuan, Wei, Yao, Yunyan, Moodera, Jagadeesh S., Maekawa, Sadamichi, Han, Wei, and Shi, Jing. Fri . "Dirac surface state–modulated spin dynamics in a ferrimagnetic insulator at room temperature". United States. doi:10.1126/sciadv.aas8660. https://www.osti.gov/servlets/purl/1499918.
@article{osti_1499918,
title = {Dirac surface state–modulated spin dynamics in a ferrimagnetic insulator at room temperature},
author = {Tang, Chi and Song, Qi and Chang, Cui-Zu and Xu, Yadong and Ohnuma, Yuichi and Matsuo, Mamoru and Liu, Yawen and Yuan, Wei and Yao, Yunyan and Moodera, Jagadeesh S. and Maekawa, Sadamichi and Han, Wei and Shi, Jing},
abstractNote = {This work demonstrates markedly modified spin dynamics of magnetic insulator (MI) by the spin momentum–locked Dirac surface states of the adjacent topological insulator (TI), which can be harnessed for spintronic applications. As the Bi concentration x is systematically tuned in 5-nm-thick (BixSb1-x)2Te3 TI films, the weight of the surface relative to bulk states peaks at x = 0.32 when the chemical potential approaches the Dirac point. At this concentration, the Gilbert damping constant of the precessing magnetization in 10-nm-thick Y3Fe5O12 MI films in the MI/TI heterostructures is enhanced by an order of magnitude, the largest among all concentrations. In addition, the MI acquires additional strong magnetic anisotropy that favors the in-plane orientation with similar Bi concentration dependence. These extraordinary effects of the Dirac surface states distinguish TI from other materials such as heavy metals in modulating spin dynamics of the neighboring magnetic layer.},
doi = {10.1126/sciadv.aas8660},
journal = {Science Advances},
issn = {2375-2548},
number = 6,
volume = 4,
place = {United States},
year = {2018},
month = {6}
}

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Works referenced in this record:

Experimental Realization of a Three-Dimensional Topological Insulator, Bi2Te3
journal, June 2009


Topological field theory of time-reversal invariant insulators
journal, November 2008

  • Qi, Xiao-Liang; Hughes, Taylor L.; Zhang, Shou-Cheng
  • Physical Review B, Vol. 78, Issue 19, Article No. 195424
  • DOI: 10.1103/PhysRevB.78.195424