Spin-singlet ground state of the coupled Jeff = 1/2 alternating chain system Sr2Co(SeO3)3
Dr. Raman Sankar and his group, in collaboration with Prof. Yang-Yuan Chen (IoP, Academia Sinica), Prof. Kwang-Yong Choi at Sungkyunkwan University (Republic of Korea) and Prof. I.P. Muthuselvam at Banaras Hindu University (India), investigated the structural, magnetic, thermodynamic, and electronic properties of a coupled Jeff = 1/2 alternating chain Sr2Co(SeO3)3 compound using magnetic susceptibility χ(T ), magnetic specific heat Cm(T ), magnetization, and neutron diffraction measurements along with first-principles calculations. The first-principles calculations based on the density functional theory suggest that Sr2Co(SeO3)3 forms a quasi-one-dimensional chain with bond alternation and interchain interactions. χ(T ), Cm(T ), and neutron powder diffraction measurements confirm that no long-range magnetic ordering occurs down to 100 mK. Instead, a maximum in χ(T ) and Cm(T ) and an exponential drop of χ(T ) and Cp(T ) as T → 0 K point to a spin-singlet ground state. The analysis of χ(T ) and Cm(T ) based on a J1-J2 alternating Heisenberg model shows the bond alternation α = J2/J1 ≈ 0.7 and a spin gap of Δ ≈ 3 K. Finally, this work demonstrates that Sr2Co(SeO3)3 is a coupled alternating chain system based on spin-orbit entangled Jeff = 1/2.
Journal Links: https://journals.aps.org/prb/abstract/10.1103/PhysRevB.106.214417