Related Experiment Video
Updated: Aug 7, 2026
![The Synthesis of [Sn10(Si(SiMe3)3)4]2- Using a Metastable Sn(I) Halide Solution Synthesized via a Co-condensation Technique](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F54498.jpg&w=3840&q=50)
The Synthesis of [Sn10(Si(SiMe3)3)4]2- Using a Metastable Sn(I) Halide Solution Synthesized via a Co-condensation Technique
Published on: November 28, 2016
Inverse Design of Photoinduced Structural Phase Transitions in Monolayer Metal Diiodides MI2 (M = Sn, Pb, Hg, Mg)
Runke Zhan1,2, Shuangyi Xu1,2, Rui Xu1,2
1School of Physics, Sun Yat-sen University, Guangzhou510275, China.
None:
Photoinduced structural phase transitions (PISPTs) in two-dimensional (2D) materials offer an ultrafast and noninvasive route to access structures and properties unavailable under dark conditions. However, discovering PISPTs remains challenging because illumination fundamentally reshapes the energy landscape and invalidates conventional ground state searches. Here, we develop an inverse-design method for the unbiased exploration of photostabilized phases by using the photomodified Gibbs free energy as the global variable function. Applying this method to 2D metal diiodides, we identify nonvolatile terahertz (THz)-driven PISPTs in monolayer MI2 (M = Sn, Pb, Hg, Mg). First-principles calculations show that the THz-stabilized SnI2-Pmmn and HgI2-C2/m phases exhibit significantly enhanced and anisotropic optical absorption. Moreover, the THz-stabilized HgI2-P4m2 and PbI2-Pmm2 phases host switchable fractional quantum ferroelectric states with in-plane polarizations and low switching barriers, suggesting nonvolatile and reversible phase transitions. Our work reveals rich opportunities for photoinduced structural phase engineering in 2D materials with emergent optical and ferroelectric properties.
More Related Videos
Related Concept Videos
Stereoisomerism
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
Thermal Sigmatropic Reactions: Overview
Sigmatropic shifts are classified based on an order term [i, j ], where i and j indicate the number of atoms across which each end of the σ bond migrates. Below are examples of a [3,3] sigmatropic shift in 1,5-hexadiene, referred to as...
Crystal Field Theory - Tetrahedral and Square Planar Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
Phase Transitions: Sublimation and Deposition

