Electron–Phonon and Spin–Lattice Coupling in Atomically Thin Layers of MnBi2Te4
- Univ. of Texas, Austin, TX (United States)
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Texas Tech Univ., Lubbock, TX (United States)
- Univ. of the Basque Country (UPV/EHU), Leioa (Spain)
- Univ. of Texas, Austin, TX (United States); Academia Sinica, Taipei (Taiwan)
- Academia Sinica, Taipei (Taiwan)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Northeastern Univ., Boston, MA (United States); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
MnBi2Te4 represents a new class of magnetic topological insulators in which novel quantum phases emerge at temperatures higher than those found in magnetically doped thin films. Here in this paper, we investigate how couplings between electron, spin, and lattice are manifested in the phonon spectra of few-septuple-layer thick MnBi2Te4. After categorizing phonon modes by their symmetries, we study the systematic changes in frequency, line width, and line shape of a spectrally isolated A1g mode. The electron–phonon coupling increases in thinner flakes as manifested in a broader phonon line width, which is likely due to changes of the electron density of states. In 4- and 5-septuple thick samples, the onset of magnetic order below the Néel temperature is concurrent with a transition to an insulating state. We observe signatures of a reduced electron–phonon scattering across this transition as reflected in the reduced Fano parameter. Finally, spin–lattice coupling is measured and modeled from temperature-dependent phonon frequency.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division; National Science Foundation (NSF); Welch Foundation; Ministry of Science and Technology (Taiwan)
- Grant/Contract Number:
- 89233218CNA000001; AC05-00OR22725; DMR-1760668; F-1662
- OSTI ID:
- 1827588
- Alternate ID(s):
- OSTI ID: 1819515
- Report Number(s):
- LA-UR-21-23905
- Journal Information:
- Nano Letters, Vol. 21, Issue 14; ISSN 1530-6984
- Publisher:
- American Chemical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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