Structural and Electrical Properties of Be _x Zn_1–x O Alloys under High Pressure

Abstract

We conduct extensive research into the structures of Be x Zn1 – x O ternary alloys in a pressure range of 0–60 GPa, using the ab initio total energy evolutionary algorithm and total energy calculations, finding several metastable structures. Our pressure-composition phase diagram is constructed using the enthalpy results. In addition, we calculate the electronic structures of the Be x Zn1 – x O structures and investigate the bandgap values at varying pressures and Be content. The calculated results show that the bandgap of the Be x Zn1 – x O ternary alloys increases with an increase in Be content at the same pressure. Moreover, the bandgap of the Be x Zn1 – x O ternary alloys increases with the increasing pressure with fixed Be content. At the same Be content, the formation enthalpy of the Be x Zn1 – x O ternary alloys first decreases, then increases with the increasing pressure.

Two different emission enhancement of trans-stilbene crystal under high pressure: Different evolution of structure

“….C interactions played the main role, which would responsible for the second decrease of PL emission. [17,20,41]…”

“…The molecule arrangement is expected to be modified easily by external stress, thus tuning the optical properties. [20,21] In this work, the high pressure optical properties of transstilbene crystal were explored by in situ high pressure PL spectra. And then the dispersive x-ray diffraction (ADXRD), Raman spectroscopy, and theory calculation were performed to explore the mechanisms of pressure-tune optical behavior for trans-stilbene crystal from the structural point of view.…”

Bandgap evolution of Mg3N2 under pressure: Experimental and theoretical studies

“…The increasing covalent component is considered to be responsible for the widening of the bandgap. [25][26][27][28] The evolution of the Mg 3 N 2 bandgap should take into account two effects: on one hand, the shortened atomic distances under pressure induce widening of both the valence band and the conduction band, which tend to reduce the bandgap. On the other hand, the shortened bond length increases the overlap of the electron cloud, accompanying with the enhanced covalent bond, which tends to widen the bandgap.…”

First principle studies of TiO2-ZnO alloys under high pressure

“…Therefore, the application of ZnO-based semiconductor alloys is particularly important. In recent years, a series of studies have been carried out on ZnO-based semiconductor alloys using first-principles calculations, such as with MgO, CaO, BeO and SnO [7][8][9][10]. Due to the large difference of ion radius between Be and Zn, the structure of BeZnO is thermodynamically unstable.…”