Electron-phonon coupling and hot electron thermalization in titanium nitride

We have studied the thermalization of hot carriers in both pristine and defective titanium nitride (TiN) using a two-temperature model. All parameters of this model, including the electron-phonon coupling parameter, were obtained from first-principles density-functional theory calculations. The virtual-crystal approximation was used to describe defective systems. We find that thermalization of hot carriers occurs on much faster timescales than in gold as a consequence of the significantly stronger electron-phonon coupling in TiN. Specifically, the largest thermalization times, on the order of 200 femtoseconds, are found in TiN with nitrogen vacancies for electron temperatures around 4000 K.

我们使用双温模型研究了原始氮化钛（TiN）和有缺陷的氮化钛中热载流子的热化过程。该模型的所有参数，包括电子 - 声子耦合参数，均通过第一性原理密度泛函理论计算得出。采用虚拟晶体近似来描述有缺陷的系统。我们发现，由于TiN中电子 - 声子耦合明显更强，热载流子的热化在比金快得多的时间尺度上发生。具体而言，在电子温度约为4000 K时，在具有氮空位的TiN中发现最大的热化时间约为200飞秒。