Large elastic anisotropy in Brillouin scattering of copper-intercalated GaS and GaSe

D Daniel Paulo-Wach (Department of Materials Science and Engineering, University of California Berkeley 1 , Berkeley, California 94720,) E Ethan Chen M Masaru Nakamura (Okinawa Churashima Foundation Research Institute) O Oscar D. Dubon (Department of Materials Science and Engineering, University of California Berkeley 1 , Berkeley, California 94720,) K Kristie J. Koski (Department of Chemistry, University of California, Davis, 1 Shields Avenue, Davis, California 95616, United States)

Abstract

Brillouin scattering of bulk layered hexagonal gallium sulfide (GaS) and gallium selenide (GaSe) was measured both as pristine materials and intercalated with copper and silver. The sound velocities, refractive index, and four of the five independent elastic stiffnesses (cij) were determined. Values of the c11 elastic stiffness in thin crystals are higher than in previous measurements, bringing the elastic anisotropy (c11/c33) into a range typical of other layered materials. Copper intercalation showed a larger effect on acoustic phonons in GaS than in GaSe.

Article Details

Volume / Issue Vol. 127, Issue 26
Published December 29, 2025
ISSN 0003-6951
Publisher American Institute of Physics

Journal Info

Applied Physics Letters

American Institute of Physics

ISSN: 0003-6951 Physical Sciences

Authors (5)

D

Daniel Paulo-Wach

Department of Materials Science and Engineering, University of California Berkeley 1 , Berkeley, California 94720,

E

Ethan Chen

M

Masaru Nakamura

Okinawa Churashima Foundation Research Institute

O

Oscar D. Dubon

Department of Materials Science and Engineering, University of California Berkeley 1 , Berkeley, California 94720,

K

Kristie J. Koski

Department of Chemistry, University of California, Davis, 1 Shields Avenue, Davis, California 95616, United States