Phonon-phonon interactions in photoexcited graphite studied by ultrafast electron diffraction

被引：29

作者：

Harb, M. ^{[1
,2
,3
]}

Enquist, H. ^{[1
]}

Jurgilaitis, A. ^{[1
]}

Tuyakova, F. T. ^{[4
,5
]}

Obraztsov, A. N. ^{[5
,6
]}

Larsson, J. ^{[7
]}

机构：

[1] Lund Univ, MAX Lab, POB 118, Lund, Sweden

[2] Drexel Univ, Dept Phys, Philadelphia, PA 19104 USA

[3] Drexel Univ, Dept Mat Sci & Engn, Philadelphia, PA 19104 USA

[4] Moscow Tech Univ MIREA, Moscow, Russia

[5] Univ Eastern Finland, Dept Math & Phys, Joensuu 80101, Finland

[6] Moscow MV Lomonosov State Univ, Dept Phys, Moscow 119991, Russia

[7] Lund Univ, Atom Phys Div, Dept Phys, POB 118, Lund, Sweden

来源：

PHYSICAL REVIEW B | 2016年 / 93卷 / 10期

基金：

俄罗斯科学基金会; 瑞典研究理事会;

关键词：

HEAT;

D O I：

10.1103/PhysRevB.93.104104

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

We investigated phonon-phonon interactions in photoexcited single-crystalline graphite by ultrafast electron diffraction. Transient electron diffraction profiles from a 35 nm graphite film were observed following laser excitation. Changes in intensities of diffraction spots revealed a two-exponential relaxation process with <0.5 ps and similar to 8 ps time scales. Furthermore, the transient thermal diffuse scattering signal showed evidence for population of phonons across the Gamma K and Gamma M branches of the phonon dispersion spectrum on a <2 ps time scale. Based on these dynamics, we conclude that the fast relaxation process corresponds to decay of strongly coupled optical phonons, and the slow relaxation process to redistribution of phonon energy to the equilibrium thermal distribution.

引用

页数：7