Giant Modulation of Refractive Index from Picoscale Atomic Displacements.

It is shown that structural disorder-in the form of anisotropic, picoscale atomic displacements-modulates the refractive index tensor and results in the giant optical anisotropy observed in BaTiS, a quasi-1D hexagonal chalcogenide. Single-crystal X-ray diffraction studies reveal the presence of antipolar displacements of Ti atoms within adjacent TiS chains along the c-axis, and threefold degenerate Ti displacements in the a-b plane. Ti solid-state NMR provides additional evidence for those Ti displacements in the form of a three-horned NMR lineshape resulting from a low symmetry local environment around Ti atoms.

Pronounced interplay between intrinsic phase-coexistence and octahedral tilt magnitude in hole-doped lanthanum cuprates.

Definitive understanding of superconductivity and its interplay with structural symmetry in the hole-doped lanthanum cuprates remains elusive. The suppression of superconductivity around 1/8th doping maintains particular focus, often attributed to charge-density waves (CDWs) ordering in the low-temperature tetragonal (LTT) phase. Central to many investigations into this interplay is the thesis that LaBaCuO and particularly LaEuSrCuO present model systems of purely LTT structure at low temperature.

Metastable disordered phase in flash-frozen Prussian Blue analogues.

A new metastable phase in flash-frozen disordered Prussian blue analogues is reported. The phase is characterised by the appearance of diffuse scattering clouds and the reduction of the local structure symmetry: from cubic to a tetragonal or lower space group. The phase transition is characterised by the translational modulation of the structure and is likely caused by the freezing of the water confined in the pores of the structure.

Elucidating 2D Charge-Density-Wave Atomic Structure in an MX-Chain by the 3D-ΔPair Distribution Function Method.

The front cover artwork is provided by Prof. Masahiro Yamashita's group at Tohoku University and designed by Dr. Laurent Guérin at University of Rennes 1.

Elucidating 2D Charge-Density-Wave Atomic Structure in an MX-Chain by the 3D-ΔPair Distribution Function Method.

Many solids, particularly low-dimensional systems, exhibit charge density waves (CDWs). In one dimension, charge density waves are well understood, but in two dimensions, their structure and their origin are difficult to reveal. Herein, the 2D charge-density-wave atomic structure and stabilization mechanism in the bromide-bridged Pd compound [Pd(cptn) Br]Br (cptn=1R,2R-diaminocyclopentane) is investigated by means of single-crystal X-ray diffraction employing the 3D-Δpair distribution function (3D-ΔPDF) method.

Emerging spin-phonon coupling through cross-talk of two magnetic sublattices.

Many material properties such as superconductivity, magnetoresistance or magnetoelectricity emerge from the non-linear interactions of spins and lattice/phonons. Hence, an in-depth understanding of spin-phonon coupling is at the heart of these properties. While most examples deal with one magnetic lattice only, the simultaneous presence of multiple magnetic orderings yield potentially unknown properties.

Striping of orbital-order with charge-disorder in optimally doped manganites.

The phase diagrams of LaMnO perovskites have been intensely studied due to the colossal magnetoresistance (CMR) exhibited by compositions around the [Formula: see text] doping level. However, phase segregation between ferromagnetic (FM) metallic and antiferromagnetic (AFM) insulating states, which itself is believed to be responsible for the colossal change in resistance under applied magnetic field, has prevented an atomistic-level understanding of the orbital ordered (OO) state at this doping level. Here, through the detailed crystallographic analysis of the phase diagram of a prototype system (AMn[Formula: see text]Mn[Formula: see text]O), we show that the superposition of two distinct lattice modes gives rise to a striping of OO Jahn-Teller active Mn and charge disordered (CD) Mn layers in a 1:3 ratio.

Spin-ice physics in cadmium cyanide.

Spin-ices are frustrated magnets that support a particularly rich variety of emergent physics. Typically, it is the interplay of magnetic dipole interactions, spin anisotropy, and geometric frustration on the pyrochlore lattice that drives spin-ice formation. The relevant physics occurs at temperatures commensurate with the magnetic interaction strength, which for most systems is 1-5 K.

A Vacancy-Driven Intermetallic Phase: RhCd (δ ∼ 0.56).

A nonstoichiometric line phase, RhCd (δ ∼ 0.56), is found in close vicinity to RhCd and structurally characterized by single-crystal X-ray diffraction and energy-dispersive X-ray spectroscopy. The compound crystallizes in the cubic space group 3 (No.

Designing disorder into crystalline materials.

Crystals are a state of matter characterized by periodic order. Yet, crystalline materials can harbour disorder in many guises, such as non-repeating variations in composition, atom displacements, bonding arrangements, molecular orientations, conformations, charge states, orbital occupancies or magnetic structure. Disorder can sometimes be random but, more usually, it is correlated.

Function from configurational degeneracy in disordered framework materials.

The existence of correlated disorder in molecular frameworks is an obvious mechanism by which unusual cooperative phenomena might be realised. We show that the use of local-symmetry lowering approaches can allow ostensibly high-symmetry framework structures to harbour exotic disordered states often studied in the context of spin lattice models. These states exhibit strongly cooperative behaviour that might be exploited in anomalous mechanical, host/guest, and information storage behaviour.

Hidden diversity of vacancy networks in Prussian blue analogues.

Prussian blue analogues (PBAs) are a diverse family of microporous inorganic solids, known for their gas storage ability, metal-ion immobilization, proton conduction, and stimuli-dependent magnetic, electronic and optical properties. This family of materials includes the double-metal cyanide catalysts and the hexacyanoferrate/hexacyanomanganate battery materials. Central to the various physical properties of PBAs is their ability to reversibly transport mass, a process enabled by structural vacancies.

Layered Zn[Co(CN)](CHCOO) double metal cyanide: a two-dimensional DMC phase with excellent catalytic performance.

Double metal cyanides (DMCs) are well known, industrially applied catalysts for ring opening polymerization reactions. In recent years, they have been studied for a variety of catalytic reactions, as well as other applications, such as energy storage and Cs sorption. Herein, a new, layered DMC phase (), Zn[Co(CN)](CHCOO)·4HO, was synthesized.

The Mystery of the AuIn 1:1 Phase and Its Incommensurate Structural Variations.

In this communication, the AuIn 1:1 phase ( Naturwissenschaften , 1953 , 40 , 437 , DOI: 10.1007/BF00590353 ), and its ordering behavior at various temperatures is investigated. To enable the growth of a X-ray suitable specimen, a tempering routine was established by the interpretation of a differential scanning calorimetry (DSC) study.

Design of crystal-like aperiodic solids with selective disorder-phonon coupling.

Functional materials design normally focuses on structurally ordered systems because disorder is considered detrimental to many functional properties. Here we challenge this paradigm by showing that particular types of strongly correlated disorder can give rise to useful characteristics that are inaccessible to ordered states. A judicious combination of low-symmetry building unit and high-symmetry topological template leads to aperiodic 'procrystalline' solids that harbour this type of disorder.

Structure of decagonal Al-Ni-Rh.

The crystal structure of the decagonal phase in the system Al-Ni-Rh (d-Al-Ni-Rh) was analyzed in the five-dimensional embedding approach based on single-crystal synchrotron X-ray diffraction data. The structure can be described as a quasiperiodic packing of partially overlapping decagonal and pentagonal columnar clusters with ∼ 21 Å diameter and ∼ 4 Å period along the tenfold axis.

A new complex intermetallic phase in the system Al-Cu-Ta with familiar clusters and packing principles.

The structure of hP386-Al(57.4)Cu(3.6)Ta(39.