Institute of Solid State Chemistry, Urals Branch of the Russian Academy of Sciences, Pervomayskaya 91, GSP-145, Yekaterinburg, Russia.
J Phys Condens Matter. 2010 Nov 3;22(43):435802. doi: 10.1088/0953-8984/22/43/435802. Epub 2010 Oct 11.
The relaxation of excited electrons in the conduction band of titanium dioxide with the rutile and anatase structure is investigated by means of a first-principle method. The evaluations are based on the pseudo-potential plane-wave approach to the electronic band structure calculations, the density-functional perturbation theory for the calculations of phonons and electron-phonon interactions, and on the 'Fermi golden rule' for evaluations of the electron relaxation time and the energy loss time. We demonstrate two regimes of the electron relaxation. For the excited electrons with energy less than 0.01 eV above the conduction band bottom the relaxation occurs in the pico-second timescale, whereas at higher excitation energies the electron relaxation time is within a few femto-seconds and the energy loss time is within a few tens of femto-seconds.
采用第一性原理方法研究了金红石和锐钛矿结构二氧化钛中导带中受激电子的弛豫。评估基于电子能带结构计算的赝势平面波方法、声子和电子-声子相互作用计算的密度泛函微扰理论以及电子弛豫时间和能量损失时间的“费米黄金法则”。我们展示了电子弛豫的两种模式。对于能量低于导带底以上 0.01eV 的受激电子，弛豫发生在皮秒时间尺度内，而在更高的激发能下，电子弛豫时间在几个飞秒内，能量损失时间在几十飞秒内。
