CaMn2Sb2: Spin waves on a frustrated antiferromagnetic honeycomb lattice
- Stony Brook Univ., NY (United States)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Brookhaven National Lab. (BNL), Upton, NY (United States); Stony Brook Univ., NY (United States)
Here we present inelastic neutron scattering measurements of the antiferromagnetic insulator , which consists of corrugated honeycomb layers of Mn. The dispersion of magnetic excitations has been measured along the H and L directions in reciprocal space, with a maximum excitation energy of ≈ 24 meV. These excitations are well described by spin waves in a Heisenberg model, including first-and second-neighbor exchange interactions J1 and J2 in the Mn plane and also an exchange interaction between planes. The determined ratio J2/J1 ≈ 1/6 suggests that is an example of a compound that lies very close to the mean field tricritical point, known for the classical Heisenberg model on the honeycomb lattice, where the Néel phase and two different spiral phases coexist. Lastly, the magnitude of the determined exchange interactions reveals a mean field ordering temperature ≈ 4 times larger than the reported Néel temperature TN = 85 K, suggesting significant frustration arising from proximity to the tricritical point.
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC00112704; AC02-98CH10886; AC05-00OR22725
- OSTI ID:
- 1226029
- Alternate ID(s):
- OSTI ID: 1182460; OSTI ID: 1261437; OSTI ID: 1265506
- Report Number(s):
- BNL-108226-2015-JA; R&D Project: PO010; PM009; KC0201060; KC0202020
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 91, Issue 18; ISSN 1098-0121
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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