论文标题
lioso $ _3 $的极性顺序过渡上方的扩展关键波动区域的证据
Evidence for an extended critical fluctuation region above the polar ordering transition in LiOsO$_3$
论文作者
论文摘要
金属lioso $ _3 $经历低于$ t_c $ = 140 K以下的连续铁电结构相变，以实现极地金属。为了理解驱动这种过渡的微观相互作用，我们通过机电耦合 - 由短距离偶极 - 偶极 - 偶极相关引起的晶格的扭曲来研究其临界行为，这是由液体偶发引起的。通过绘制从lioso $ _3 $中的第二个谐波电峰辐射的全部角度分布并进行简化的超极化键模型分析，我们发现了从$ t_c $延长的较大温度范围内，从$ t_c $延伸到230 k的较大温度范围内，较大的质量为230 k，在不合格的li-li-li-li-li-li-bond中变化。这种临界波动的扩展区域可能解释了在特定的热量和拉曼散射数据中报告的异常特征，并表明存在现有理论处理中未考虑的竞争相互作用。从更广泛的角度来看，我们的结果表明，机电效应如何充当金属中反转对称性破坏过渡的临界行为的探针。
Metallic LiOsO$_3$ undergoes a continuous ferroelectric-like structural phase transition below $T_c$ = 140 K to realize a polar metal. To understand the microscopic interactions that drive this transition, we study its critical behavior above $T_c$ via electromechanical coupling - distortions of the lattice induced by short-range dipole-dipole correlations arising from Li off-center displacements. By mapping the full angular distribution of second harmonic electric-quadrupole radiation from LiOsO$_3$ and performing a simplified hyper-polarizable bond model analysis, we uncover subtle symmetry-preserving lattice distortions over a broad temperature range extending from $T_c$ up to around 230 K, characterized by non-uniform changes in the short and long Li-O bond lengths. Such an extended region of critical fluctuations may explain anomalous features reported in specific heat and Raman scattering data, and suggests the presence of competing interactions that are not accounted for in existing theoretical treatments. More broadly, our results showcase how electromechanical effects serve as a probe of critical behavior near inversion symmetry breaking transitions in metals.
