Magnetic excitation spectrum and Hamiltonian of the quantum spin chain compound BaCuTe2O6

Samartzis, A.; Chillal, S.; Jeschke, H. O.; Voneshen, D. J.; Lu, Z.; Islam, A. T. M. N.; Lake, B.

Abstract

Abstract

The magnetic excitation spectrum and Hamiltonian of the quantum magnet BaCuTe2O6 is studied by inelastic neutron scattering (INS) and density functional theory (DFT). INS on powder and single crystal samples reveals overlapping spinon continua—the spectrum of an antiferromagnetic spin-1/2 spin chain—due to equivalent chains running along the a, b, and c directions. Long-range magnetic order onsets below TN=6.3 K due to interchain interactions, and is accompanied by the emergence of sharp spin-wave excitations, which replace the continua at low energies. The spin-wave spectrum is highly complex and was successfully modelled achieving excellent agreement with the data. The extracted interactions reveal an intrachain interaction, J3=2.9 meV, while the antiferromagnetic hyperkagome interaction J2 is the subleading interaction responsible for coupling the chains together in a frustrated way. DFT calculations reveal a similar picture for BaCuTe2O6 of dominant J3 and subleading J2 antiferromagnetic interactions and also indicate a high sensitivity of the interactions to small changes of structure, which could explain the very different Hamiltonians observed in the sister compounds SrCuTe2O6 and PbCuTe2O6.

Citation

Samartzis, A., Chillal, S., Jeschke, H. O., Voneshen, D. J., Lu, Z., Islam, A. T. M. N., & Lake, B. (2023). Magnetic excitation spectrum and Hamiltonian of the quantum spin chain compound BaCuTe2O6. Physical Review B, 107(18), https://doi.org/10.1103/physrevb.107.184435

• Journal Article Type: Article
• Acceptance Date: May 5, 2023
• Online Publication Date: May 18, 2023
• Publication Date: 2023
• Deposit Date: May 19, 2023
• Publicly Available Date: May 22, 2023
• Journal: Physical Review B
• Print ISSN: 2469-9950
• Electronic ISSN: 2469-9969
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 107
• Issue: 18
• DOI: https://doi.org/10.1103/physrevb.107.184435