论文标题
对热厅对同位素替代的巨大抑制作用钛酸盐效应
Sizeable suppression of thermal Hall effect upon isotopic substitution in strontium titanate
论文作者
论文摘要
我们报告了原始和同位素取代的钛酸盐的单晶中热厅效应的测量。我们发现了$ srti^{16} o_3 $和$^{18} o $ $ -enriched $ srti^{18} o_3 $样品之间的托架电导率的两个数量级差异。在大多数温度范围内，$ srti^{18} o_3 $中的热霍尔电导率（$κ_{xy} $）的大小与纵向导热率（$κ__{xx} $）的大小成比例，这暗示了拼音介导的热室效应。但是，它们在最大的温度下偏离，热厅角度比（$ | |κ_{xy}/κ_{xx} | $）表现出异常降低行为，低于铁电温度$ t_c $ t_c $〜$〜$ 25 k $。该观察结果表明了一种新的潜在机制，因为常规场景无法解释声子频谱略有变化中的这种差异。值得注意的是，$ srti^{18} O_3 $在$ srti^{18}中迅速降低热厅角度比的大小差异与该位移铁电的量子临界波动的强度相关。这种关系指出了钛酸盐质量子物理学与其热霍尔效应之间的联系，这可能是解释非磁性绝缘系统中外来现象的示例的可能线索。
We report measurements of the thermal Hall effect in single crystals of both pristine and isotopically substituted strontium titanate. We discovered a two orders of magnitude difference in the thermal Hall conductivity between $SrTi^{16}O_3$ and $^{18}O$-enriched $SrTi^{18}O_3$ samples. In most temperature ranges, the magnitude of thermal Hall conductivity ($κ_{xy}$) in $SrTi^{18}O_3$ is proportional to the magnitude of the longitudinal thermal conductivity ($κ_{xx}$), which suggests a phonon-mediated thermal Hall effect. However, they deviate in the temperature of their maxima, and the thermal Hall angle ratio ($|κ_{xy}/κ_{xx}|$) shows anomalously decreasing behavior below the ferroelectric Curie temperature $T_c$ ~$25 K$. This observation suggests a new underlying mechanism, as the conventional scenario cannot explain such differences within the slight change in phonon spectrum. Notably, the difference in magnitude of thermal Hall conductivity and rapidly decreasing thermal Hall angle ratio in $SrTi^{18}O_3$ is correlated with the strength of quantum critical fluctuations in this displacive ferroelectric. This relation points to a link between the quantum critical physics of strontium titanate and its thermal Hall effect, a possible clue to explain this example of an exotic phenomenon in non-magnetic insulating systems.
