Robust phonon engineering and symmetry-selective lattice dynamics in CrSBr 1–x Cl x

Authors:
Open Access
Publisher website
Google Scholar
Abstract
Atomic substitution provides a controlled route to engineer lattice dynamics in low-symmetry two-dimensional materials. Here, by combining polarization-resolved Raman spectroscopy and first-principles calculations, we investigate the evolution of phonon characteristics in CrSBr 1 − x Cl x ( 0 ⩽ x ⩽ ∼ 0.5 ) upon partial substitution of Br with Cl atoms. Progressive Cl substitution of Br induces systematic shifts of parent CrSBr out-of-plane A g phonon modes and activates additional Raman features. These features persist across different polarization configurations and excitation energies, reflecting substitution-induced symmetry lowering and local lattice perturbations. Explicit supercell phonon calculations combined with Raman Γ -density-of-states simulations identify these features as symmetry-lowered descendants of parent modes arising from alloy disorder. Complementary strain-dependent calculations reveal that anisotropic lattice compression plays a key role in renormalizing Cr–S dominated phonons. Under near-resonant excitation, stimulated Raman scattering-like amplification remains observable with increasing Cl content, highlighting the resilience of anisotropic electron–phonon coupling in this system.
Funding Information
  • Grantová Agentura České Republiky (23-06174K)
  • Akademie Věd České Republiky (LQ200402201)
  • Ministerstvo Školství, Mládeže a Tělovýchovy (CZ.02.01.01/00/22 008/0004558)
  • Research Council of Finland (358944)
  • Deutsche Forschungsgemeinschaft (FB-1415-417590517)

This publication has 36 references indexed in Scilit: