Abstract
In a collinear antiferromagnet with easy-axis anisotropy, symmetry guarantees that the spin wave modes are doubly degenerate. The two modes carry opposite spin angular momentum and exhibit opposite chirality. Using a honeycomb antiferromagnet in the presence of the Dzyaloshinskii-Moriya interaction, we show that a longitudinal temperature gradient can drive the two modes to opposite transverse directions, realizing a spin Nernst effect of magnons with vanishing thermal Hall current. We find that magnons around the Γ point and the K point contribute oppositely to the transverse spin transport, and their competition leads to a sign change of the spin Nernst coefficient at finite temperature. Possible material candidates are discussed.
Original language | English |
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Article number | 217202 |
Journal | Physical Review Letters |
Volume | 117 |
Issue number | 21 |
DOIs | |
State | Published - Nov 15 2016 |
Funding
We are grateful to Ying Ran for insightful discussions. We would also like to thank Igor Barsukov, Matthew W. Daniels, Nikhil Sivadas, and Jimmy Zhu for useful comments. R. C. and D. X. were supported by the Department of Energy, Basic Energy Sciences, Grant No. DE-SC0012509. S. O. acknowledges support by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division.