标题： 用集成自旋缺陷温度计研究悬浮钻石纳米结构中的热传输 显示英文标题

标题： Imaging heat transport in suspended diamond nanostructures with integrated spin defect thermometers

摘要： 在所有材料中，单晶金刚石具有最高的测量热导率之一，在室温下的值高于2000 W/m/K。这是由于动量守恒的“正常”声子-声子散射过程占主导地位，而非动量耗散的“Umklapp”过程，这一特性也表明金刚石是实验研究违反傅里叶定律的声子热传输现象的理想平台。在这里，我们引入稀释的氮空位色心作为原位、高精度的自旋缺陷温度计，以成像从环境条件加热的单晶金刚石微结构中的温度不均匀性。我们分析了横截面范围约为0.2到2.6$\mathrm{\mu m}^2$的悬臂梁，观察到横截面与热通量之间的关系偏离了傅里叶定律的预测。我们依靠基于线性化声子玻尔兹曼输运方程的第一性原理模拟来解释这种行为，还讨论了制造引起的杂质如何影响导电性。我们的温度成像方法可以应用于任意几何形状的金刚石器件，为探索非常规的、非扩散的热传输现象铺平了道路。 显示英文摘要

摘要： Among all materials, mono-crystalline diamond has one of the highest measured thermal conductivities, with values above 2000 W/m/K at room temperature. This stems from momentum-conserving `normal' phonon-phonon scattering processes dominating over momentum-dissipating `Umklapp' processes, a feature that also suggests diamond as an ideal platform to experimentally investigate phonon heat transport phenomena that violate Fourier's law. Here, we introduce dilute nitrogen-vacancy color centers as in-situ, highly precise spin defect thermometers to image temperature inhomogeneities in single-crystal diamond microstructures heated from ambient conditions. We analyze cantilevers with cross-sections in the range from about 0.2 to 2.6 $\mathrm{\mu m}^2$, observing a relation between cross-section and heat flux that departs from Fourier's law predictions. We rationalize such behavior relying on first-principles simulations based on the linearized phonon Boltzmann transport equation, also discussing how fabrication-induced impurities influence conduction. Our temperature-imaging method can be applied to diamond devices of arbitrary geometry, paving the way for the exploration of unconventional, non-diffusive heat transport phenomena.