Prediction of structure candidates for zinc oxide as a function of pressure and investigation of their electronic properties

Zagorac, Dejan; Schön, J. Christian; Zagorac, Jelena; Jansen, Martin

doi:10.1103/physrevb.89.075201

Cited by 74 publications

(51 citation statements)

References 100 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similar theoretical investigations have also been conducted for crystalline ZnO materials in the search for viable polymorphs at ambient conditions [35][36][37] and at high pressures 38 . Most hypothetical structures proposed in above studies are however strongly metastable, with formation energies significantly higher than both the WZ and ZB structures.…”

Section: Introductionmentioning

confidence: 89%

Energy landscape of ZnO clusters and low-density polymorphs

et al. 2017

View full text Add to dashboard Cite

We report on an extensive study of ZnO materials with cage-like motives in clusters and bulk phases through structural searches using the minima hopping method. A novel putative ground state was discovered for the (ZnO)32 cluster with a tube-like structure, closely related to the previously reported (ZnO)24 ground state cage geometry. Furthermore, the effect of ionization on the geometries and energetic ordering of (ZnO)n clusters with n = 3 − 10, 12 was studied by directly sampling the energy landscape of the ionized system. Our results indicate that the transition from ring and planar structures to 3D cages occurs at larger cluster sizes than in the neutral system. Inspired by the bottom-up design philosophy and the predominance of cage-like structures in medium-sized clusters, a search for crystalline ZnO was conducted aimed specifically at low density polymorphs, resulting in the discovery of 57 novel metastable phases. The voids in these low-density materials closely resemble the hollow cage structures of small (ZnO)n/(ZnO) + n clusters with n < 16. In analogy to clathrate materials, these voids could serve to accommodate guest atoms to tailor the materials properties for various applications.

show abstract

Section: Introductionmentioning

confidence: 89%

Energy landscape of ZnO clusters and low-density polymorphs

et al. 2017

View full text Add to dashboard Cite

show abstract

“…12 For the evaluation of the Coulomb summation, the method proposed by DeLeeuw was employed. 12 For the evaluation of the Coulomb summation, the method proposed by DeLeeuw was employed.…”

Section: Methodsmentioning

confidence: 99%

“…10,11 As described in detail in the methods section, we proceeded in two steps during the global exploration of the energy landscape of zinc oxide: rst, a number of local minima were identied using simulated annealing as a global optimization procedure, 8,12 and in a second step, these minima served as starting points for further global explorations using the threshold algorithm. At low or medium temperatures, such regions consist of local minima surrounded by sufficiently high energy barriers.…”

Section: Introductionmentioning

confidence: 99%

Theoretical investigations of novel zinc oxide polytypes and in-depth study of their electronic properties

et al. 2015

Self Cite

View full text Add to dashboard Cite

Zinc oxide is one of the most investigated compounds in materials science, both experimentally and theoretically, while in nature it appears only rarely, as the mineral zincite. Yet there are still many open questions: Is it still possible to observe or synthesize new modifications of zinc oxide? And can we improve the properties of a material that has already been investigated in thousands of studies? What is the connection between zincite, zinc sulfide and zinc oxide, and can we finally explain the controversial mineral matraite? In short, Yes: the answer to these questions is polytypism. We identify a multitude of possible stable polytypes for zinc oxide, and we show that by varying the stacking order, we can finetune the electronic properties such as the direct primary and secondary band gaps in zinc oxide without adding dopant atoms. Fig. 1 Visualization of the experimentally observed (a and b) and calculated (c-i) modifications of zinc oxide: (a) wurtzite (2H) type; (b) sphalerite (3C) type; (c) 4H polytype; (d) 5H polytype; (e) 6H polytype; (f) 8H polytype; (g) 9R polytype; (h) 12R polytype; (i) 15R polytype.This journal is

show abstract

“…In these polymorphs, the zinc and oxygen atoms experience different environments, especially when some reduction of dimensionality takes place, which may strongly modify the electronic properties. Bulk gap widths and densities of states (DOS) have been scrutinized by first principles simulations 10,11 and we have recently disentangled the effects of band narrowing and of electrostatics in the modifications of quasi particle, absorption and electron energy loss spectra 12 . Beyond bulk properties, the possibility of tuning electronic and optical properties through a reduction of dimensionality has fostered advances in the fabrication and structural characterization of ZnO nanostructures [13][14][15][16][17][18][19] and thin films on various substrates [20][21][22][23][24][25][26][27][28][29][30] , with a range of techniques and under a variety of experimental conditions.…”

Section: Introductionmentioning

confidence: 99%

Confinement effects in ultrathin ZnO polymorph films: Electronic and optical properties

2016

View full text Add to dashboard Cite

Relying on generalized-gradient and hybrid first-principles simulations, this work provides a complete characterization of the electronic properties of ZnO ultra-thin films, cut along the BodyCentered-Tetragonal(010), Cubane(100), h-BN(0001), Zinc-Blende(110), Wurtzite (1010) and (0001) orientations. The characteristics of the local densities of states are analyzed in terms of the reduction of the Madelung potential on under-coordinated atoms and surface states/resonances appearing at the top of the VB and bottom of the CB. The gap width in the films is found to be larger than in the corresponding bulks, which is assigned to quantum confinement effects. The components of the high frequency dielectric constant are determined and the absorption spectra of the films are computed. They display specific features just above the absorption threshold due to transitions from or to the surface resonances. This study provides a first understanding of finite size effects on the electronic properties of ZnO thin films and a benchmark which is expected to foster experimental characterization of ultra-thin films via spectroscopic techniques.

show abstract

Prediction of structure candidates for zinc oxide as a function of pressure and investigation of their electronic properties

Cited by 74 publications

References 100 publications

Energy landscape of ZnO clusters and low-density polymorphs

Energy landscape of ZnO clusters and low-density polymorphs

Theoretical investigations of novel zinc oxide polytypes and in-depth study of their electronic properties

Confinement effects in ultrathin ZnO polymorph films: Electronic and optical properties

Contact Info

Product

Resources

About