Abstract
CsYbSe2 has an ideal triangular-lattice geometry with pronounced two-dimensionality, pseudospin-1/2 nature, and the absence of structural disorder. These excellent characteristics favor a quantum spin-liquid realization in this material. In this work, we applied quasihydrostatic compression methods to explore the structural behaviors. Our study reveals that CsYbSe2 undergoes a structural transition around 24 GPa, accompanied by a large volume collapse of ΔV/V0∼13%. The ambient hexagonal structure with the space group P63/mmcis lowered to the tetragonal structure (P4/mmm) under high pressure. Meanwhile, the color of CsYbSe2 changes gradually from red to black before the transition. Dramatic pressure-induced changes are clarified by the electronic structure calculations from the first principles, which indicate that the initial insulating ground state turns metallic in a squeezed lattice. These findings highlight Yb-based dichalcogenide delafossites as an intriguing material to probe novel quantum effects under high pressure.
| Original language | English |
|---|---|
| Article number | 174106 |
| Journal | Physical Review B |
| Volume | 108 |
| Issue number | 17 |
| DOIs | |
| State | Published - Nov 1 2023 |
Funding
This work was supported by the National Science Foundation (NSF) CAREER Award No. DMR-2045760. L.Y. is supported by NSF Grant No. DMR-2124934. This work uses the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by NSF Grant No. ACI-1548562. The authors acknowledge the Texas Advanced Computing Center (TACC) at The University of Texas at Austin for providing HPC resources. Research at Oak Ridge National Laboratory (ORNL) is supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), Materials Sciences and Engineering Division. This research used resources of the Advanced Photon Source, a U.S. DOE Office of Science user facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. Uses of the COMPRES-GSECARS gas loading system and the program were supported by COMPRES (NSF Grant No. EAR-1661511) and GSECARS (NSF Grant No. EAR-1634415 and DOE Grant No. DE-FG02-94ER14466). Use of the GSECARS Raman Lab System was supported by the NSF MRI Proposal (Grant No. EAR-1531583). We thank Dr. Young Jay Ryu for his kind help with gas loading in DACs at the APS.