Mapping the lattice dynamical anomaly of the order parameters across the Verwey transition in magnetite
Mapping the lattice dynamical anomaly of the order parameters across the Verwey transition in magnetite
复制标题
DOI：
10.1088/1367-2630/aa83a3
复制
发表时间：
2017-10-12
影响因子：
3.3
通讯作者：
Carbone, F.
中科院分区：
文献类型：
--
作者：
Borroni, S.;Tucker, G. S.;Carbone, F.
我们提出了非弹性中子散射数据在磁铁矿的Verwey过渡，通过解孪晶方法获得的单晶。我们提供了直接的证据的影响的电荷顺序的横向声学声子，与不连续硬化和变窄的转变温度，和能量分裂为不同的极化。这与横向光学X-3模式的行为形成对比，与理论预期相反，横向光学X-3模式不存在任何临界异常。我们的数据表明，在临界温度以上发生的无公度波动成为锁定在晶格的过渡点，通过一种类似于固体表面上的二维液体结晶的机制。我们的结果也有助于澄清不同的动力学和相互作用的电子和结构模式在Verwey转变。
We present inelastic neutron scattering data across the Verwey transition in magnetite, obtained for a single crystal via a detwinning method. We provide direct evidence of the influence of the charge order on the transverse-acoustic phonons, associated with discontinuous hardening and narrowing at the transition temperature, and energy splitting for different polarizations. This contrasts with the behavior of the transverse-optical X-3 mode, which does not present any critical anomaly, contrary to theoretical expectations. Our data indicate that the incommensurate fluctuations occurring above the critical temperature become locked to the lattice at the transition point, through a mechanism similar to the crystallization of a two-dimensional liquid on a solid surface. Our results also contribute to clarify the different dynamics and mutual interactions of the electronic and structural modes in the Verwey transition.