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Title: Polarization-resolved Raman spectroscopy of α RuCl 3 and evidence of room-temperature two-dimensional magnetic scattering

Abstract

Polarization-resolved Raman spectroscopy was performed and analyzed from large, high-quality, monodomain single crystal of α–RuCl3, a proximate Kitaev quantum spin liquid. Spectra were collected with laser polarizations parallel and perpendicular to the honeycomb plane. Pairs of nearly degenerate phonons were discovered and show either a fourfold or twofold polarization angle dependence in their Raman intensity, thereby providing evidence to definitively assign the bulk crystal point group as C2h. The low-frequency continuum that is often attributed to scattering from pairs of Majorana fermions was also examined and found to disappear when the laser excitation and scattered photon polarizations were perpendicular to the honeycomb plane. This disappearance, along with the behavior of the phonon spectrum in the same polarization configuration, strongly suggests that the scattering continuum is two-dimensional. Here, we argue that this scattering continuum originates from the Kitaev magnetic interactions that survives up to room temperature, a scale larger than the bare Kitaev exchange energy of approximately 50 K.

Authors:
 [1];  [2];  [3];  [4];  [5]; ORCiD logo [3]; ORCiD logo [6];  [3];  [2]; ORCiD logo [7]
  1. The Ohio State Univ., Columbus, OH (United States); National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States)
  2. National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States)
  3. Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  4. National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States); Univ. of Maryland, College Park, MD (United States)
  5. Towson Univ., MD (United States); National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States)
  6. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  7. The Ohio State Univ., Columbus, OH (United States)
Publication Date:
Research Org.:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES); NSF MRSEC
OSTI Identifier:
1606815
Grant/Contract Number:  
AC05-00OR22725; DMR-1420451
Resource Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 100; Journal Issue: 13; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; magnetism; majorana fermions; phonons; quantum spin liquid; spin liquid; Raman spectroscopy

Citation Formats

Mai, Thuc T., McCreary, Amber, Lampen-Kelley, Paige, Butch, N. P., Simpson, J. R., Yan, J. -Q., Nagler, Stephen E., Mandrus, David, Walker, A. R. Hight, and Aguilar, Raul Valdés. Polarization-resolved Raman spectroscopy of α–RuCl3 and evidence of room-temperature two-dimensional magnetic scattering. United States: N. p., 2019. Web. doi:10.1103/PhysRevB.100.134419.
Mai, Thuc T., McCreary, Amber, Lampen-Kelley, Paige, Butch, N. P., Simpson, J. R., Yan, J. -Q., Nagler, Stephen E., Mandrus, David, Walker, A. R. Hight, & Aguilar, Raul Valdés. Polarization-resolved Raman spectroscopy of α–RuCl3 and evidence of room-temperature two-dimensional magnetic scattering. United States. https://doi.org/10.1103/PhysRevB.100.134419
Mai, Thuc T., McCreary, Amber, Lampen-Kelley, Paige, Butch, N. P., Simpson, J. R., Yan, J. -Q., Nagler, Stephen E., Mandrus, David, Walker, A. R. Hight, and Aguilar, Raul Valdés. Mon . "Polarization-resolved Raman spectroscopy of α–RuCl3 and evidence of room-temperature two-dimensional magnetic scattering". United States. https://doi.org/10.1103/PhysRevB.100.134419. https://www.osti.gov/servlets/purl/1606815.
@article{osti_1606815,
title = {Polarization-resolved Raman spectroscopy of α–RuCl3 and evidence of room-temperature two-dimensional magnetic scattering},
author = {Mai, Thuc T. and McCreary, Amber and Lampen-Kelley, Paige and Butch, N. P. and Simpson, J. R. and Yan, J. -Q. and Nagler, Stephen E. and Mandrus, David and Walker, A. R. Hight and Aguilar, Raul Valdés},
abstractNote = {Polarization-resolved Raman spectroscopy was performed and analyzed from large, high-quality, monodomain single crystal of α–RuCl3, a proximate Kitaev quantum spin liquid. Spectra were collected with laser polarizations parallel and perpendicular to the honeycomb plane. Pairs of nearly degenerate phonons were discovered and show either a fourfold or twofold polarization angle dependence in their Raman intensity, thereby providing evidence to definitively assign the bulk crystal point group as C2h. The low-frequency continuum that is often attributed to scattering from pairs of Majorana fermions was also examined and found to disappear when the laser excitation and scattered photon polarizations were perpendicular to the honeycomb plane. This disappearance, along with the behavior of the phonon spectrum in the same polarization configuration, strongly suggests that the scattering continuum is two-dimensional. Here, we argue that this scattering continuum originates from the Kitaev magnetic interactions that survives up to room temperature, a scale larger than the bare Kitaev exchange energy of approximately 50 K.},
doi = {10.1103/PhysRevB.100.134419},
journal = {Physical Review B},
number = 13,
volume = 100,
place = {United States},
year = {Mon Oct 14 00:00:00 EDT 2019},
month = {Mon Oct 14 00:00:00 EDT 2019}
}

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Cited by: 18 works
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Figures / Tables:

FIG. 1 FIG. 1: Crystal structure and Laue X-ray diffraction pattern. Crystal structure of α-RuCl3 projected onto the a-c plane (a) and a-b plane (b). The solid black lines represent the unit cell. The orange balls represent Cl atoms, while the larger blue balls represent Ru atoms. (c) Picture of studied sample;more » the red circles are the approximate location of where the Laue patterns in (d) and (e) were taken. The well defined circular dots indicate the single-crystallinity of our sample. This pattern remained unchanged over several millimeters on the a-b plane surface. The relationship between the crystallographic axes (a,b,c) and the laboratory (Raman tensor) coordinate (x,y,z) is shown in (f). Notice that c and z are not parallel.« less

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Works referencing / citing this record:

Field-induced QCD 3 -Chern-Simons quantum criticalities in Kitaev materials
journal, January 2020


Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.