Department of Materials Science and Engineering and Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA.
Phys Rev Lett. 2012 Oct 26;109(17):175503. doi: 10.1103/PhysRevLett.109.175503.
Weak electron-phonon coupling in Au and Cu produces a significant thermal resistance when heat flows from a thin Pt layer into a thin Au or Cu layer on picosecond time scales. Metal bilayers (Pt/Au and Pt/Cu) were prepared by magnetron sputter deposition; thermal transport in the bilayers was studied by time domain thermoreflectance in the temperature range 38<T<300 K. Analysis of heat transfer in the bilayer yields the electron-phonon coupling parameter g(T) of Au and Cu. Our results for g(T) are consistent with the temperature dependence predicted by the two-temperature model of Kaganov et al. [Sov. Phys. JETP 4, 173 (1957)] and help bridge the gap between data obtained using pump-probe spectroscopy at room temperature and electrical measurements at low temperatures.
当热量在皮秒时间尺度上从薄的 Pt 层流向薄的 Au 或 Cu 层时，Au 和 Cu 中的弱电子-声子耦合在产生显著的热阻。通过磁控溅射沉积制备了金属双层（Pt/Au 和 Pt/Cu）；在 38<T<300 K 的温度范围内，通过时域热反射率研究了双层中的热传输。对双层中的热传递进行分析，得到了 Au 和 Cu 的电子-声子耦合参数 g(T)。我们的 g(T)结果与 Kaganov 等人的双温模型[Sov. Phys. JETP 4, 173 (1957)]预测的温度依赖性一致，并有助于弥合在室温下使用泵浦探测光谱获得的数据与低温下的电测量之间的差距。
