Photoinduced charge-density-wave dynamics in $K0.3MoO3$

See, e.g., Charge Density Waves in Solids, edited by L. P. Gor’kov and G. Gruner (North Holland, Amsterdam, 1989);

Density Waves in Solids, edited by G. Grüner (Addison-Wesley, Reading, MA, 1994).

D.

Mihailovic

,

D.

Dvorsek

,

V. V.

Kabanov

,

J.

Demsar

,

L.

Forro

, and

H.

Berger

, , ().

E.

Beaurepaire

,

J.-C.

Merle

,

A.

Daunois

, and

J.-Y.

Bigot

, , ().

B.

Koopmans

,

M.

van Kampen

,

J. T.

Kohlhepp

, and

W. J. M.

de Jonge

, , ().

R. A.

Kaindl

,

M.

Woerner

,

T.

Elsaesser

,

D. C.

Smith

,

J. F.

Ryan

,

G. A.

Farnan

,

M. P.

McCurry

, and

D. G.

Walmsley

, , ().

T.

Kise

,

T.

Ogasawara

,

M.

Ashida

,

Y.

Tomioka

,

Y.

Tokura

, and

M.

Kuwata-Gonokami

, , ().

J.

Demsar

,

K.

Biljakovic

, and

D.

Mihailovic

, , ().

A. A.

Tsvetkov

,

D. M.

Sagar

,

P. H. M.

van Loosdrecht

,

D.

van der Marel D

, and

S.

van Smaalen

, , ().

B.

Zawilski

,

J.

Richard

, and

J.

Marcus

, , ().

See, e.g., Femtosecond Laser Pulses: Principles and Experiments, edited by C. Rullière (Springer, New York, 1998).

G.

Travaglini

,

I.

Morke

, and

P.

Wachter

, , ().

J. P.

Pouget

,

B.

Hennion

,

C.

Escribe-Filippini

, and

M.

Sato

, , ().

B. P.

Gorshunov

,

A. A.

Volkov

,

G. V.

Kozlov

,

L.

Degiorgi

,

A.

Blank

,

T.

Csiba

,

M.

Dressel

,

Y.

Kim

,

A.

Schwartz

, and

G.

Grüner

, , ().

A.

Virosztek

and

K.

Maki

, , ().

We can exclude the explanation of the photoexcitation of coherent longitudinal acoustic phonons (CLAPs) from the anisotropy of the coherent oscillations (Fig. 3) and damping. For KMO, the reflectivity (Ref. 17) and the optical conductivity (Ref. 13) is isotropic for wavelengths in the visible range, i.e., photon energy $>2 eV.$ Therefore, photoexcitation of CLAPs would result in polarization-independent (isotropic) oscillations of $ΔR$ at 400 nm probe wavelength.

B.

Hennion

,

J. P.

Pouget

, and

M.

Sato

, , (). A factor of $2π$ is missing in the calculation of the phason velocity which had been included in Ref. 12.

G.

 

Travaglini

,

P.

 

Wachter

,

J.

 

Marcus

, and

C.

 

Schlenker

,  , ();

G.

Travaglini

,

P.

Wachter

,

J.

Marcus

, and

C.

Schlenker

, , ().

S.

Girault

,

A. H.

Moudden

, and

J. P.

Pouget

, , ().

The anisotropy cannot be explained by the optical properties of $K0.3MoO3$ since the reflectivity and optical conductivity is isotropic at photon energies above 2 eV (Refs. 13 and 17).

Since the penetration depth, ξ, in KMO is very small $(∼100 nm),$ the momentum bandwidth of the excited coherent collective modes must be large: from $δqδx>1$ and $δx∼ξ∼100 nm$ it follows that $δq>1×105 cm−1,$ i.e., larger than the biggest $q$ probe used. Hence, we expect to generate a broad band of collective modes, comparable to the entire range of probe wavelengths.

C.

Thomsen

,

H. T.

Grahn

,

H. J.

Maris

, and

J.

Tauc

, , ().

H.-Y.

 

Hao

and

H. J.

 

Maris

,  , ();

H.-Y.

Hao

and

H. J.

Maris

, , ().