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Unusual heat transport of the Kitaev material Na$_2$Co$_2$TeO$_6$: putative quantum spin liquid and low-energy spin excitations
- Source :
- Phys. Rev. B 104, 144426 (2021)
- Publication Year :
- 2021
-
Abstract
- We studied the field dependent thermal conductivity ($\kappa$) of Na$_2$Co$_2$TeO$_6$, a compound considered as the manifestation of the Kitaev model based on the high-spin $d^7$ Co$^{2+}$ ions. We found that in-plane magnetic fields beyond a critical value $B_c \approx$~10 T are able to drastically enhance $\kappa$ at low temperatures, resulting in a double-peak structure of $\kappa(T)$ that closely resembles the behavior of $\alpha$-RuCl$_3$. This result suggests that heat transport in Na$_2$Co$_2$TeO$_6$ is primarily phononic, and it is strongly affected by scattering from magnetic excitations that are highly tunable by external fields. Interestingly, for magnetic fields $B // a$ (i.e., along the zigzag direction of the Co-Co bonds), there is an extended field range which separates the long-range magnetic order for $B\leq B_c\approx10$ T and the partially spin-polarized gapped high-field phase for $B\gtrsim 12$ T. The low-energy phonon scattering is particularly strong in this field range, consistent with the notion that the system becomes a quantum spin liquid with prominent spin fluctuations down to energies of no more than 2 meV.
- Subjects :
- Condensed Matter - Strongly Correlated Electrons
Subjects
Details
- Database :
- arXiv
- Journal :
- Phys. Rev. B 104, 144426 (2021)
- Publication Type :
- Report
- Accession number :
- edsarx.2101.12199
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.1103/PhysRevB.104.144426