Response to Comment on "Reversible disorder-order transitions in atomic crystal nucleation".

Taking the Si(111)√3×√3–Ag surface as an example, it has been investigated how the atomic arrangement of the probe tip affects obtained scanning tunneling microscope (STM) images using first-principles theoretical calculations. Various shapes of the tip were represented by tilting the symmetry axes of four kinds of clusters consisting of several tungsten atoms. Tips having a few equivalent atoms at their apexes produce distinctly different STM images from experiment if their symmetry axes are normal to the sample surface. Even in these cases, however, calculated STM images become similar to the observed ones by tilting the symmetry axes. This fact indicates that only one atom at the tip apex gives essential contribution to the tunneling current. Furthermore, it can be explained why good images can be obtained, in spite of the fact that the shape of experimental STM tips must be quite arbitrary on the atomic scale.

Pressure-dependent compressibility of K2X(CO3)2 (X = Ca, Mg) under high pressure

Structural behavior and electrical transport properties of Mg2Ge under high pressure

Ultrahigh elasticity and anomalous softening of α-Ag2S under pressure

Shape memory alloys (SMA's) are a special kind of metal alloys with unique structural properties, such as shape memory effect (SME) and pseudo-elasticity (SE) that were well-observed in TiNi alloy, which commercially trades as Nitinol. This polymorphic crystal behaviour arose from the reversible phase transition between an ordered high-temperature B2 and low-temperature martensite phase (L10/B19/B19′). Due to the high ductility of Ru, this work employed a supercell approach to track the effect of nickel addition on highly stable B2-Ti50Ru50 with the intent to stimulate SME. Thermodynamic, mechanical, electronic structure and lattice dynamic characteristics were estimated using first-principles calculations. The phonons spectra of B2 Ti50Ru50 consisted of only positive frequencies, but the addition of Ni above 18.75 at. % resulted in positive and negative frequencies, indicative of a possible martensitic transformation, which is a strong character for SME.

Size and shape dependent order–disorder phase transition of Co–Pt nanowires

Transition metal nitrides (TMNs) have attracted extensive research attention owing to their excellent physical and chemical properties. As an important branch of TMNs, molybdenum nitrides exhibit unique mechanical, electrical, and optical properties, and thus have broad application prospects in supercapacitors and hydrogen production via water splitting. In recent years, substantial progress has been made in the synthesis of molybdenum nitride crystals, with various methods developed to prepare different molybdenum nitride phases. Notably, gas-phase clusters with controlled composition, size, and structure play a pivotal role in the nucleation and growth of molybdenum nitride crystals, making cluster research critical to understanding the synthesis mechanisms of molybdenum nitrides. Previous studies have reported the fabrication of highly dispersed molybdenum nitride cluster catalysts and confirmed that atomically dispersed clusters serve as key active sites for catalytic reactions. In this work, we constructed a series of molybdenum nitride cluster structures based on the configurations of various bulk molybdenum nitrides. First-principles calculations were performed to evaluate the stability of these clusters and identify the most stable configurations. In addition, we investigated the structural evolution trends of the clusters under different chemical potentials.

Effective first-principle description of thermodynamics for BCC Nb-V system by involving the contributions of chemical order, lattice distortion and vibration

Symmetry breaking and switchable thermal dielectric behaviors triggered by order-disorder phase transition in a neutral co-crystallized organic adduct

Intrinsic disorder is at the center of biochemical regulation and is particularly overrepresented among the often multifunctional viral proteins. Replication and transcription of the respiratory syncytial virus (RSV) relies on a RNA polymerase complex with a phosphoprotein cofactor P as the structural scaffold, which consists of a four-helix bundle tetramerization domain flanked by two domains predicted to be intrinsically disordered. Because intrinsic disorder cannot be reduced to a defined atomic structure, we tackled the experimental dissection of the disorder-order transitions of P by a domain fragmentation approach. P remains as a tetramer above 70 °C but shows a pronounced reversible secondary structure transition between 10 and 60 °C. While the N-terminal module behaves as a random coil-like IDP in a manner independent of tetramerization, the isolated C-terminal module displays a cooperative and reversible metastable transition. When linked to the tetramerization domain, the C-terminal module becomes markedly more structured and stable, with strong ANS binding. Therefore, the tertiary structure in the C-terminal module is not compact, conferring "late" molten globule-like IDP properties, stabilized by interactions favored by tetramerization. The presence of a folded structure highly sensitive to temperature, reversibly and almost instantly formed and broken, suggests a temperature sensing activity. The marginal stability allows for exposure of protein binding sites, offering a thermodynamic and kinetic fine-tuning in order-disorder transitions, essential for the assembly and function of the RSV RNA polymerase complex.

Order-disorder transition in Li0.5Al2.5O4

The underlying mechanism of the strain-induced reversible magnetic state transition in MXene nanosheets

We report reversible phase transitions of ZnO nanowires subjected to high-pressure diamond anvil cell experiments. It was found that Mn doping obviously changes the elastic stability of ZnO nanowires and leads to low critical pressures of the reversible transitions between wurtzite to rocksalt phases during compression and decompression. First-principles calculations demonstrate that the lower critical pressures caused by Mn doping are associated with the decrease of internal energy difference and the increase of relative volume change between wurtzite to rocksalt phases.

Theoretical calculations of the scanning tunneling microscopy images of the Si(111) √3 × √3-Ag surface: effects of the tip shape

Interactions in Fe-Pd were studied using diffuse x-ray scattering and first-principles calculations. Diffuse x-ray scattering was performed from single crystals of Fe--38.2 at. % Pd and Fe--81.0 at. % Pd to investigate states of thermal equilibrium at 1023 K and 1073 K, respectively. Short-range-order scattering was separated and effective pair interaction (EPI) parameters were determined using the inverse Monte Carlo method. The EPI parameters are found to strongly vary with respect to data from a previous investigation of Fe--50 at. % Pd. Electronic-structure calculations of effective cluster interaction (ECI) parameters for these states showed the importance of considering multibody interactions and applying the disordered local moment model of the magnetic state: in the ferromagnetic model, the strength of the interactions gets overestimated. Close agreement is reached for short-range order between calculations and the present scattering experiments. Using either a linear compositional variation of the EPI parameters or ECI parameters for alloys with other Pd fractions, the shape of the order-disorder transition line on the Pd-rich side could be reproduced.