Magnon Pairs and Spin-Nematic Correlation in the Spin-Seebeck Effect

TL;DR

This paper explores how spin-nematic correlations in a frustrated magnet suppress the spin-Seebeck effect by stabilizing magnon pairs, providing new insights into magnetic excitations and spin transport.

Contribution

It demonstrates the field-induced suppression of SSE linked to spin-nematic correlations and magnon pair formation in LiCuVO$_4$, combining experimental and theoretical analysis.

Findings

Suppression of SSE occurs above 2 T despite linear magnetization.

Spin-nematic correlations grow with increasing magnetic field.

Magnon pairs with spin-2 stabilize, reducing spin injection.

Abstract

Investigating exotic magnetic materials with spintronic techniques is effective at advancing magnetism as well as spintronics. In this work, we report unusual field-induced suppression of the spin-Seebeck effect (SSE) in a quasi one-dimensional frustrated spin-$\frac{1}{2}$ magnet LiCuVO$_4$, known to exhibit spin-nematic correlation in a wide range of external magnetic field $B$. The suppression takes place above $|B| > 2$ T in spite of the $B$-linear isothermal magnetization curves in the same $B$ range. The result can be attributed to the growth of the spin-nematic correlation while increasing $B$. The correlation stabilizes magnon pairs carrying spin-2, thereby suppressing the interfacial spin injection of SSE by preventing the spin-1 exchange between single magnons and conduction electrons at the interface. This interpretation is supported by integrating thermodynamic measurements and theoretical analysis on the SSE.