Optical magnons with dominant bond-directional exchange interactions in the honeycomb lattice iridate ? ? Li<sub>2</sub>IrO<sub>3</sub> [electronic resource]
Saved in:
| Online Access: |
Full Text (via OSTI) |
|---|---|
| Corporate Author: | |
| Format: | Government Document Electronic eBook |
| Language: | English |
| Published: |
Washington, D.C. : Oak Ridge, Tenn. :
United States. Department of Energy. Office of Science ; Distributed by the Office of Scientific and Technical Information, U.S. Department of Energy,
2021.
|
| Subjects: |
| Abstract: | We have used resonant inelastic x-ray scattering to reveal optical magnons in a honeycomb lattice iridate <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>?</mi><mo>-</mo><mrow><msub><mi>Li</mi><mn>2</mn></msub><msub><mi>IrO</mi><mn>3</mn></msub></mrow></math>. The spectrum in the energy region 20?25 meV exhibits momentum dependence, of which energy is highest at the location of the magnetic Bragg peak, <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo>(</mo><mi>h</mi><mo>,</mo><mi>k</mi><mo>)</mo><mo>=</mo><mo>(</mo><mo>ł</mo><mn>0.32</mn><mo>,</mo><mn>0</mn><mo>)</mo></mrow></math>, and lowered toward <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo>(</mo><mn>0</mn><mo>,</mo><mn>0</mn><mo>)</mo></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo>(</mo><mo>ł</mo><mn>1</mn><mo>,</mo><mn>0</mn><mo>)</mo></mrow></math>. We compare our data with a linear spin-wave theory based on a generic nearest-neighbor spin model. We find that a dominant bond-directional Kitaev interaction of order 20 meV is required to explain the energy scale observed in our study. The observed excitations are understood as stemming from optical magnon modes whose intensity is modulated by a structure factor, resulting in the apparent momentum dependence. We also observed diffuse magnetic scattering arising from the short-range magnetic correlation well above <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>T</mi><mi>N</mi></msub></math>. In contrast to <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msub><mi>Na</mi><mn>2</mn></msub><msub><mi>IrO</mi><mn>3</mn></msub></mrow></math>, this diffuse scattering lacks the <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>C</mi><mn>3</mn></msub></math> rotational symmetry of the honeycomb lattice, suggesting that the bond anisotropy is far from negligible in <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>?</mi><mo>-</mo><mrow><msub><mi>Li</mi><mn>2</mn></msub><msub><mi>IrO</mi><mn>3</mn></msub></mrow></math> |
|---|---|
| Item Description: | Published through Scitech Connect. 01/27/2021. "Journal ID: ISSN 2469-9950." "Other: 165100." ": US2209171." Chun, Sae Hwan ; Stavropoulos, P. Peter ; Kee, Hae-Young ; Sala, M. Moretti ; Kim, Jungho ; Kim, Jong-Woo ; Kim, B. J. ; Mitchell, J. F. ; Kim, Young-June ; Natural Sciences and Engineering Research Council of Canada (NSERC) National Research Foundation of Korea (NRF) |
| Physical Description: | Size: Article No. L020410 : digital, PDF file. |