Inorganic SnIP‐Type Double Helices in Main‐Group Chemistry

Abstract

Inspired by the synthesis of the first atomic-scale double-helix semiconductor SnIP, this study deals with the question of whether more atomistic, inorganic double-helix compounds are accessible. With the aid of quantum chemical calculations, we have identified 31 candidates by a homoatomic substitution in MXPn, varying the Group 14 M-element from Si to Pb, the Group 17 X-element from F to I and replacing the pnictide (Pn) phosphorus by arsenic. The double-helical structure of SnIP has been used as the starting model for all candidates and the electronic structure and vibrational spectra were determined within the framework of density functional theory (DFT). Varying the outer MX or the inner Pn helix led to the conclusion that iodide- and bromide-containing MXPn compounds show similar structures to SnIP. Here, the calculations indicate interesting effects for electronic band-gap tuning. For the highly polarized fluorides, a segregation of the helices to more complex MX substructures is predicted.

Degenerate topological line surface phonons in quasi-1D double helix crystal SnIP

“…81 In addition, by atomic substitution, a large material family with double helix structures has been predicted using first-principles calculations, providing a wide range of band gaps between 1 and 2.5 eV. 82 With a tunable band gap and high mechanical flexibility, these quasi-one-dimensional semiconductors are extremely promising for next generation devices ranging from mechanical sensors to optoelectronics. 81,82 Moreover, they can serve as a material platform to realize one-dimensional physical models such as the Su-Schrieffer-Heeger model 83 and Majorana quantum wires.…”

“…82 With a tunable band gap and high mechanical flexibility, these quasi-one-dimensional semiconductors are extremely promising for next generation devices ranging from mechanical sensors to optoelectronics. 81,82 Moreover, they can serve as a material platform to realize one-dimensional physical models such as the Su-Schrieffer-Heeger model 83 and Majorana quantum wires. 84,85 Bulk SnIP crystallizes in the monoclinic space group P2/c (No.…”

SnBrP‐A SnIP‐type representative in the Sn−Br−P system

“…DFT calculations on 32 different MXPn compounds (M=Si, Ge, Sn, Pb; X=F, Cl, Br, I; Pn=P, As) illustrate, that 17 of them should possess the double helical SnIP structure. [17] Calculated band gaps of SnIP-type compounds may vary between 1.2-1.8 eV (PBE functionals), while HSE06 calculations resulted in band gaps of 2.21-2.96 eV. [18] Band edge positions meet the fundamental requirement for the oxidation and reduction in water splitting reaction.…”

Atomic and electronic structure of solids of Ge2Br2PN, Ge2I2PN, Sn2Cl2PN, Sn2Br2PN and Sn2I2PN inorganic double helices: a first principles study

“…Following the discovery of SnIP inorganic double helices, recently a theoretical study has predicted other double helices of ABP type in the same group, where A ¼ Si-Pb and B ¼ Cl-I. 24 Similar to SnIP solid, these systems also stabilize in the same crystal structure.…”