Topological quantum phase transition in the Ising-like antiferromagnetic spin chain BaCo2V2O8
Topological quantum phase transition in the Ising-like antiferromagnetic spin chain BaCo2V2O8
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DOI：
10.1038/s41567-018-0126-8
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发表时间：
2018-07-01
期刊：
影响因子：
19.6
通讯作者：
Grenier, Beatrice
中科院分区：
文献类型：
--
作者：
Faure, Quentin;Takayoshi, Shintaro;Grenier, Beatrice
自从Berezinskii，Kosterlitz和Elderless的开创性想法以来，拓扑激发一直是我们理解整个新的相变类别的核心。在大多数情况下，这些过渡由单一类型的拓扑对象控制。然而，有一些情况，仍然知之甚少，其中两个对偶拓扑激发争夺控制相图和过渡。因此，寻找这种情况下的实验实现是相当感兴趣的。我们在这里表明，这种情况发生在BaCo 2 V2 O 8，自旋1/2伊辛类准一维反铁磁体，当受到横向于伊辛轴的均匀磁场。利用中子散射实验，我们测量了超过临界值的磁场的量子激发的急剧修改。通过与理论计算的比较，这种量子相变被确定为两种不同类型的孤子拓扑对象之间的转变，这两种不同类型的孤子拓扑对象被动力学结构因子的不同分量捕获。
Since the seminal ideas of Berezinskii, Kosterlitz and Thouless, topological excitations have been at the heart of our understanding of a whole novel class of phase transitions. In most cases, those transitions are controlled by a single type of topological objects. There are, however, some situations, still poorly understood, where two dual topological excitations fight to control the phase diagram and the transition. Finding experimental realizations of such cases is thus of considerable interest. We show here that this situation occurs in BaCo2V2O8, a spin-1/2 Ising-like quasi-one-dimensional antiferromagnet, when subjected to a uniform magnetic field transverse to the Ising axis. Using neutron scattering experiments, we measure a drastic modification of the quantum excitations beyond a critical value of the magnetic field. This quantum phase transition is identified, through a comparison with theoretical calculations, to be a transition between two different types of solitonic topological object, which are captured by different components of the dynamical structure factor.