Excitations of the spin-1/2 antiferromagnetic XXZ chain SrCo2V2O8 in a transverse magnetic field

The one-dimensional spin-1/2 antiferromagnetic with Heisenberg-Ising (XXZ) anisotropy is a great model system to explore fundamental physics. In zero applied magnetic field it hosts spinon excitations which are confined into pairs by interchain coupling. In a longitudinal magnetic field the long-range magnetic order is destroyed and it enters a critical regime known as a Tomonaga-Luttinger Liquid. These features have been explored using the compounds BaCo2V2O8 and SrCo2V2O8. In these compounds a transverse magnetic field has unexpectedly also been found to suppress the antiferromagnetic order and induce a quantum critical regime, this occurs due to an induced staggered magnetic field which arises from the complex g-tensor of the magnetic Co2+ ions. Here we propose to explore the spectrum of SrCo2V2O8 for several transverse magnetic fields through this quantum phase transition.

具有海森堡-伊辛（Heisenberg-Ising，XXZ）各向异性的一维自旋1/2反铁磁体，是探索基础物理问题的优质模型体系。在零外加磁场环境中，该体系会产生自旋子激发（spinon excitations），且这些激发会因链间耦合作用被束缚为自旋子对；当施加纵向磁场时，体系的长程磁序会被破坏，进而进入被称为朝永-卢特希液体（Tomonaga-Luttinger Liquid）的临界区域。上述物理特性已通过BaCo₂V₂O₈与SrCo₂V₂O₈两种化合物得到了研究验证。在这两种化合物中，科研人员意外发现横向磁场同样能够抑制反铁磁序，并诱导出量子临界区；该现象的成因是磁性Co²+离子的复g张量（g-tensor）会产生诱导交错磁场。本文拟通过调控该量子相变过程，针对多个横向磁场条件下的SrCo₂V₂O₈能谱展开研究。