Ultrafast Evolution of the Excited-State Potential Energy Surface of TiO2 Single Crystals Induced by Carrier Cooling

被引：33

作者：

Bothschafter, Elisabeth M. ^{[1
,2
]}

Paarmann, Alexander ^{[3
]}

Zijlstra, Eeuwe S. ^{[4
]}

Karpowicz, Nicholas ^{[2
]}

Garcia, Martin E. ^{[4
]}

Kienberger, Reinhard ^{[1
,2
]}

Ernstorfer, Ralph ^{[3
]}

机构：

[1] Tech Univ Munich, Dept Phys, D-85748 Garching, Germany

[2] Max Planck Inst Quantum Opt, D-85748 Garching, Germany

[3] Max Planck Gesell, Fritz Haber Inst, D-14195 Berlin, Germany

[4] Univ Kassel, D-34132 Kassel, Germany

来源：

PHYSICAL REVIEW LETTERS | 2013年 / 110卷 / 06期

关键词：

COHERENT; DYNAMICS; PHONONS; BISMUTH;

D O I：

10.1103/PhysRevLett.110.067402

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

We investigate the influence of carrier cooling dynamics in TiO2 on the excited-state potential energy surface along the A(1g) optical phonon coordinate after above band-gap excitation using ultrashort ultraviolet pulses. The large amplitude coherent oscillation observed in a pump-probe transient reflectivity measurement shows a phase shift of -0.2 pi with respect to a purely instantaneous displacive excitation. The dynamic evolution of the potential energy surface minimum of the coherent phonon coordinate is explored using accurate density functional theory calculations, which confirm a shift of the potential energy surface minimum upon resonant laser excitation and reveal a significant positive contribution to the displacive force due to the cooling of the excited hot electron-hole plasma. We show that this noninstantaneous effect can quantitatively explain the experimentally observed phase using reasonable assumptions for the parameters characterizing the excited carriers. Our work demonstrates that the fast equilibration dynamics of laser-excited nonequilibrium carrier populations can have a pronounced effect on the initial structural response of crystalline solids. DOI: 10.1103/PhysRevLett.110.067402

引用

页数：5

共 23 条

[11] The electronic structure and optical response of rutile, anatase and brookite TiO2 [J].

Landmann, M. ;

Rauls, E. ;

Schmidt, W. G. .

JOURNAL OF PHYSICS-CONDENSED MATTER, 2012, 24 (19)

[12] LATTICE-DYNAMICS AND DIELECTRIC-PROPERTIES OF INCIPIENT FERROELECTRIC TIO2 RUTILE [J].

LEE, C ;

GHOSEZ, P ;

GONZE, X .

PHYSICAL REVIEW B, 1994, 50 (18) :13379-13387

[13] 'Making the molecular movie': first frames [J].

Miller, R. J. Dwayne ;

Ernstorfer, Ralph ;

Harb, Maher ;

Gao, Meng ;

Hebeisen, Christoph T. ;

Jean-Ruel, Hubert ;

Lu, Cheng ;

Moriena, Gustavo ;

Sciaini, German .

ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES, 2010, 66 :137-156

[14] Optically excited near-surface phonons of TiO2 (110) observed by fourth-order coherent Raman spectroscopy [J].

Nomoto, Tomonori ;

Sasahara, Akira ;

Onishi, Hiroshi .

JOURNAL OF CHEMICAL PHYSICS, 2009, 131 (08)

[15] Coherent excitation of the optic phonon in Si: Transiently stimulated Raman scattering with a finite-lifetime electronic excitation [J].

Riffe, D. M. ;

Sabbah, A. J. .

PHYSICAL REVIEW B, 2007, 76 (08)

[16] Transient electronic structure and melting of a charge density wave in TbTe3 [J].

Schmitt, F. ;

Kirchmann, P. S. ;

Bovensiepen, U. ;

Moore, R. G. ;

Rettig, L. ;

Krenz, M. ;

Chu, J. -H. ;

Ru, N. ;

Perfetti, L. ;

Lu, D. H. ;

Wolf, M. ;

Fisher, I. R. ;

Shen, Z. -X. .

SCIENCE, 2008, 321 (5896) :1649-1652

[17] CHEMICAL BONDING IN RUTILE-TYPE COMPOUNDS [J].

SORANTIN, PI ;

SCHWARZ, K .

INORGANIC CHEMISTRY, 1992, 31 (04) :567-576

[18] Coherent phonon generation and the two stimulated Raman tensors [J].

Stevens, TE ;

Kuhl, J ;

Merlin, R .

PHYSICAL REVIEW B, 2002, 65 (14) :1-4

[19] FEMTOSECOND VIBRATIONAL-RELAXATION OF LARGE ORGANIC-MOLECULES [J].

TAYLOR, AJ ;

ERSKINE, DJ ;

TANG, CL .

CHEMICAL PHYSICS LETTERS, 1984, 103 (05) :430-435

[20] Ultrafast changes in lattice symmetry probed by coherent phonons [J].

Wall, S. ;

Wegkamp, D. ;

Foglia, L. ;

Appavoo, K. ;

Nag, J. ;

Haglund, R. F., Jr. ;

Staehler, J. ;

Wolf, M. .

NATURE COMMUNICATIONS, 2012, 3

← 1 2 3 →