Incommensurate chirality density wave transition in a hybrid molecular framework

Abstract

Using single-crystal X-ray diffraction we characterise the 235\,K incommensurate phase transition in the hybrid molecular framework tetraethylammonium silver(I) dicyanoargentate, [NEt${}_4$]Ag${}_3$(CN)${}_4$. We demonstrate the transition to involve spontaneous resolution of chiral [NEt${}_4$]${}^{+}$ conformations, giving rise to a state in which molecular chirality is incommensurately modulated throughout the crystal lattice. We refer to this state as an incommensurate chirality density wave (XDW) phase, which represents a fundamentally new type of chiral symmetry breaking in the solid state. Drawing on parallels to the incommensurate ferroelectric transition of NaNO${}_2$ we suggest the XDW state arises through coupling between acoustic (shear) and molecular rotoinversion modes. Such coupling is symmetry-forbidden at the Brillouin zone centre but symmetry-allowed for small but finite modulation vectors $\mathbf{q}=[0,0,q_z{]}^{\ast }$. The importance of long-wavelength chirality modulations in the physics of this hybrid framework may have implications for the generation of mesoscale chiral textures, as required for advanced photonic materials.

arXiv comment5 pages, 3 figures

References in corpus (16)

• Non-Abelian Anyons and Topological Quantum Computation
• Chiral Quantum Optics
• High Resolution Polar Kerr Effect Measurements of Sr2RuO4: Evidence for Broken Time Reversal Symmetry in the Superconducting State
• What is moving in hybrid halide perovskite solar cells?
• Chiral P-Wave Order in Sr_2RuO_4
• Spin chirality on a two-dimensional frustrated lattice
• Chiral charge-density-waves
• Chirality density wave of the 'hidden order' phase in URu${}_2$Si${}_2$
• Is Sr2RuO4 a Chiral P-Wave Superconductor?
• New Symmetries in Crystals and Handed Structures
• The chiral phase transition in charge ordered 1T-TiSe2
• Berry phase mechanism for optical gyrotropy in stripe-ordered cuprates
• Proposed Chiral Texture of the Magnetic Moments of Unit-Cell Loop Currents in the Pseudogap Phase of Cuprate Superconductors
• Kerr effect from diffractive skew scattering in chiral $p_x\pm i{p}_y$ superconductors
• Chiral spin density wave order on frustrated honeycomb and bilayer triangle lattice Hubbard model at half-filling
• Discovery of parity-violating Majorana fermions in a chiral superconductor Sr2RuO4

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