Fig. 2: Diversity of CDWs in 2D β-In2Se3.
From: Complex charge density waves in simple electronic systems of two-dimensional III2–VI3 materials
a Phonon band structure of monolayer βc-In2Se3 with significant imaginary frequencies. Two red dots highlight specific phonon modes which will be discussed later. b In-plane Mexican-hat potential energy surface (PES) of Se(m) atom of 2D βc-In2Se335. c The schematic diagram of the angular rattling motion and radial vibration of Se(m) atom with a Mexican-hat PES under thermal excitation. d Three basic local units of the CDW phase. e The ferroelectric (FE) and antiferroelectric (AFE) phases with parallel and antiparallel arrangement of basic local units. f The \(\sqrt{7}\times \sqrt{7}\) and \(2\times \sqrt{3}\) CDW orders that formed by the specific arrangement of basic local units. g The relaxed energies of various CDW phases, using the energy of βc phase as a reference.
