论文标题
NBTIN纳米带中的声子热容量和自加热的正常域
Phonon heat capacity and self-heating normal domains in NbTiN nanostrips
论文作者
论文摘要
通过在不同底物温度下测得的稳态滞后电流特性来表征薄超导NBTIN纳米绑带中的自动加热正常结构域。温度依赖性和电流的大小在不同电压下保持平衡的域，只能用声子热容量明显低于3-D Debye Phonon的预期。这种降低的热容量与同一膜的磁反应和光响应研究早期获得的值一致。在温度下，从温度TE到温度TB中的底物中的电子的热流量与（T_E^p-t_b^p）与指数P〜3成正比，这与由电子 - phonon相互作用或通过胶片/层面相互效应的电子流相互作用或通过膜/尺寸覆盖的热流的指数不同。我们将这两个发现都归因于平均晶粒尺寸对薄颗粒NBTIN膜的声子频谱的影响。我们的发现对于理解利用薄颗粒膜的超导装置中的热传输非常重要。
Self-heating normal domains in thin superconducting NbTiN nanostrips were characterized via steady-state hysteretic current-voltage characteristics measured at different substrate temperatures. The temperature dependence and the magnitude of the current, which sustains a domain in equilibrium at different voltages, can only be explained with a phonon heat capacity noticeably less than expected for 3-d Debye phonons. This reduced heat capacity coincides with the value obtained earlier from magnetoconductance and photoresponse studies of the same films. The rate of heat flow from electrons at a temperature Te to phonons in the substrate at a temperature TB is proportional to (T_e^p - T_B^p) with the exponent p~3, which differs from the exponents for heat flows mediated by the electron-phonon interaction or by escaping of 3-d Debye phonons via the film/substrate interface. We attribute both findings to the effect of the mean grain size on the phonon spectrum of thin granular NbTiN films. Our findings are significant for understanding the thermal transport in superconducting devices exploiting thin granular films.
