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Title: Structural imaging of nanoscale phonon transport in ferroelectrics excited by metamaterial-enhanced terahertz fields

Abstract

Nanoscale phonon transport is a key process that governs thermal conduction in a wide range of materials and devices. Creating controlled phonon populations by resonant excitation at terahertz (THz) frequencies can drastically change the characteristics of nanoscale thermal transport and allow a direct real-space characterization of phonon mean-free paths. Using metamaterial-enhanced terahertz excitation, we tailored a phononic excitation by selectively populating low-frequency phonons within a nanoscale volume in a ferroelectric BaTiO 3 thin film. Real-space time-resolved x-ray diffraction microscopy following THz excitation reveals ballistic phonon transport over a distance of hundreds of nm, two orders of magnitude longer than the averaged phonon mean-free path in BaTiO 3. On longer length scales, diffusive phonon transport dominates the recovery of the transient strain response, largely due to heat conduction into the substrate. The measured real-space phonon transport can be directly compared with the phonon mean-free path as predicted by molecular dynamics modeling. In conclusion, this time-resolved real-space visualization of THz-matter interactions opens up opportunities to engineer and image nanoscale transient structural states with new functionalities.

Authors:
 [1];  [2];  [3];  [1];  [1];  [4];  [1];  [1];  [1];  [1];  [1];  [1];  [4];  [1];  [3];  [5];  [1]
  1. Argonne National Lab. (ANL), Argonne, IL (United States)
  2. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
  3. Univ. of Wisconsin, Madison, WI (United States)
  4. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  5. SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States)
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1420052
Grant/Contract Number:
SC0012375; AC02-06CH11357; AC02-05CH11231; AC02-76SF00515; FG02-04ER46147; W911NF-14-1-0104
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review Materials
Additional Journal Information:
Journal Volume: 1; Journal Issue: 6; Journal ID: ISSN 2475-9953
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Zhu, Yi, Chen, Frank, Park, Joonkyu, Sasikumar, Kiran, Hu, Bin, Damodaran, Anoop R., Jung, Il Woong, Highland, Matthew J., Cai, Zhonghou, Tung, I-Cheng, Walko, Donald A., Freeland, John W., Martin, Lane W., Sankaranarayanan, Subramanian K. R. S., Evans, Paul G., Lindenberg, Aaron M., and Wen, Haidan. Structural imaging of nanoscale phonon transport in ferroelectrics excited by metamaterial-enhanced terahertz fields. United States: N. p., 2017. Web. doi:10.1103/physrevmaterials.1.060601.
Zhu, Yi, Chen, Frank, Park, Joonkyu, Sasikumar, Kiran, Hu, Bin, Damodaran, Anoop R., Jung, Il Woong, Highland, Matthew J., Cai, Zhonghou, Tung, I-Cheng, Walko, Donald A., Freeland, John W., Martin, Lane W., Sankaranarayanan, Subramanian K. R. S., Evans, Paul G., Lindenberg, Aaron M., & Wen, Haidan. Structural imaging of nanoscale phonon transport in ferroelectrics excited by metamaterial-enhanced terahertz fields. United States. doi:10.1103/physrevmaterials.1.060601.
Zhu, Yi, Chen, Frank, Park, Joonkyu, Sasikumar, Kiran, Hu, Bin, Damodaran, Anoop R., Jung, Il Woong, Highland, Matthew J., Cai, Zhonghou, Tung, I-Cheng, Walko, Donald A., Freeland, John W., Martin, Lane W., Sankaranarayanan, Subramanian K. R. S., Evans, Paul G., Lindenberg, Aaron M., and Wen, Haidan. 2017. "Structural imaging of nanoscale phonon transport in ferroelectrics excited by metamaterial-enhanced terahertz fields". United States. doi:10.1103/physrevmaterials.1.060601.
@article{osti_1420052,
title = {Structural imaging of nanoscale phonon transport in ferroelectrics excited by metamaterial-enhanced terahertz fields},
author = {Zhu, Yi and Chen, Frank and Park, Joonkyu and Sasikumar, Kiran and Hu, Bin and Damodaran, Anoop R. and Jung, Il Woong and Highland, Matthew J. and Cai, Zhonghou and Tung, I-Cheng and Walko, Donald A. and Freeland, John W. and Martin, Lane W. and Sankaranarayanan, Subramanian K. R. S. and Evans, Paul G. and Lindenberg, Aaron M. and Wen, Haidan},
abstractNote = {Nanoscale phonon transport is a key process that governs thermal conduction in a wide range of materials and devices. Creating controlled phonon populations by resonant excitation at terahertz (THz) frequencies can drastically change the characteristics of nanoscale thermal transport and allow a direct real-space characterization of phonon mean-free paths. Using metamaterial-enhanced terahertz excitation, we tailored a phononic excitation by selectively populating low-frequency phonons within a nanoscale volume in a ferroelectric BaTiO3 thin film. Real-space time-resolved x-ray diffraction microscopy following THz excitation reveals ballistic phonon transport over a distance of hundreds of nm, two orders of magnitude longer than the averaged phonon mean-free path in BaTiO3. On longer length scales, diffusive phonon transport dominates the recovery of the transient strain response, largely due to heat conduction into the substrate. The measured real-space phonon transport can be directly compared with the phonon mean-free path as predicted by molecular dynamics modeling. In conclusion, this time-resolved real-space visualization of THz-matter interactions opens up opportunities to engineer and image nanoscale transient structural states with new functionalities.},
doi = {10.1103/physrevmaterials.1.060601},
journal = {Physical Review Materials},
number = 6,
volume = 1,
place = {United States},
year = 2017,
month =
}

Journal Article:
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  • Nanoscale phonon transport is a key process that governs thermal conduction in a wide range of materials and devices. Creating controlled phonon populations by resonant excitation at terahertz (THz) frequencies can drastically change the characteristics of nanoscale thermal transport and allow a direct real-space characterization of phonon mean-free paths. Using metamaterial-enhanced terahertz excitation, we tailored a phononic excitation by selectively populating low-frequency phonons within a nanoscale volume in a ferroelectric BaTiO3 thin film. Real-space time-resolved x-ray diffraction microscopy following THz excitation reveals ballistic phonon transport over a distance of hundreds of nm, two orders of magnitude longer than the averagedmore » phonon mean-free path in BaTiO3. On longer length scales, diffusive phonon transport dominates the recovery of the transient strain response, largely due to heat conduction into the substrate. The measured real-space phonon transport can be directly compared with the phonon mean-free path as predicted by molecular dynamics modeling. This time-resolved real-space visualization of THz-matter interactions opens up opportunities to engineer and image nanoscale transient structural states with new functionalities.« less
  • We describe a new method to generate enhanced terahertz (THz) surface wave (SW) via its coupling with reversed Cherenkov radiation (RCR), excited by a sheet beam bunch which travels in a vacuum above an isotropic double negative metamaterial (DNM). The physical mechanism for the enhancement is that the DNM can support a RCR which can resonantly interact with a sheet electron beam bunch, resulting in an enhanced SW due to its coupling with the enhanced RCR. Numerical results show strong enhancement effect for the SW and RCR in the THz band. This enhanced THz radiation has potential applications to high-powermore » THz radiation sources and Cherenkov detectors which require large signals.« less
  • There is a growing interest in the mode-by-mode understanding of electron and phonon transport for improving energy conversion technologies, such as thermoelectrics and photovoltaics. Whereas remarkable progress has been made in probing phonon–phonon interactions, it has been a challenge to directly measure electron–phonon interactions at the single-mode level, especially their effect on phonon transport above cryogenic temperatures. Here in this paper, we use three-pulse photoacoustic spectroscopy to investigate the damping of a single sub-terahertz coherent phonon mode by free charge carriers in silicon at room temperature. Building on conventional pump–probe photoacoustic spectroscopy, we introduce an additional laser pulse to opticallymore » generate charge carriers, and carefully design temporal sequence of the three pulses to unambiguously quantify the scattering rate of a single-phonon mode due to the electron–phonon interaction. Our results confirm predictions from first-principles simulations and indicate the importance of the often-neglected effect of electron–phonon interaction on phonon transport in doped semiconductors.« less