Abstract
We discuss the implications that new magnetocaloric, thermal expansion, and magnetostriction data in a-RuCl3 single crystals have on its temperature-field phase diagram and uncover the magnetic-field dependence of an apparent energy gap structure ?(H) that evolves when the low-temperature antiferromagnetic order is suppressed. We show that, depending on how the thermal expansion data are modeled, ?(H) can show a cubic field dependence and remain finite at zero field, consistent with the pure Kitaev model hosting itinerant Majorana fermions and localized Z2 fluxes. Our magnetocaloric effect data provide, below 1K, unambiguous evidence for dissipative phenomena at Hc, a smoking gun for a first-order phase transition. Conversely, our results show little support for a phase transition from a QSL to a polarized paramagnetic state above Hc.
| Original language | English |
|---|---|
| Article number | 214432 |
| Journal | Physical Review B |
| Volume | 102 |
| Issue number | 21 |
| DOIs | |
| State | Published - Dec 24 2020 |
Funding
We thank M. B. Salamon, C. D. Batista, Y. Kohama, M. Lee, and V. Zapf for helpful discussions. A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by the NSF Cooperative Agreement No. DMR-1644779 the U.S. DOE and the State of Florida. This material is based upon work supported by the U.S. Department of Energy, Office of Science, National Quantum Information Science Research Centers. P.F.S.R. acknowledges support from the Los Alamos Laboratory Directed Research and Development program through project 20210064DR. D.G.M. acknowledges support from the Gordon and Betty Moore Foundation's EPiQS Initiative, Grant No. GBMF9069. J.Q.Y. acknowledges support from the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. S.N. was supported by the U.S. DOE Office of Science, Basic Energy Sciences, Division of Scientific User Facilities, and R.S., Y.T., and M.J. by the NHMFL UCGP program.