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Huge built-in electric fields are predicted to exist in wurtzite III-V nitrides thin films and multilayers. Such fields originate from heterointerface discontinuities of the macroscopic bulk polarization of the nitrides. We discuss the…

Materials Science · Physics 2007-05-23 Fabio Bernardini , Vincenzo Fiorentini

The strain induced by lattice mismatch at the interface is responsible for the different value of the band discontinuities observed recently for the AlN/GaN (AlN on GaN) and the GaN/AlN (GaN on AlN) polar (0001) interface. We present a…

Materials Science · Physics 2008-02-03 Fabio Bernardini , Vincenzo Fiorentin , David Vanderbilt

Macroscopic polarization, both of intrinsic and piezoelectric nature, is unusually strong in III-V nitrides, and the built in electric fields in the layers of nitride-based nanostructures, stemming from polarization changes at…

Materials Science · Physics 2009-10-31 Fabio Bernardini , Vincenzo Fiorentini

Huge built-in electric fields have been predicted to exist in wurtzite III-V nitrides thin films and multilayers. Such fields originate from heterointerface discontinuities of the macroscopic bulk polarization of the nitrides. Here we…

Materials Science · Physics 2009-10-31 V. Fiorentini , F. Bernardini , F. Della Sala , A. Di Carlo , P. Lugli

Huge built-in electric fields have been predicted to exist in wurtzite III-V nitrides thin films and multilayers. Such fields originate from heterointerface discontinuities of the macroscopic bulk polarization of the nitrides. Here we…

Materials Science · Physics 2007-05-23 V. Fiorentini , F. Bernardini , F. Della Sala , A. DiCarlo , P. Lugli

We study the dependence of macroscopic polarization on composition and strain in wurtzite III-V nitride ternary alloys using ab initio density-functional techniques. The spontaneous polarization is characterized by a large bowing, strongly…

Materials Science · Physics 2009-11-07 Fabio Bernardini , Vincenzo Fiorentini

Rocksalt ScN is a semiconductor with a small lattice mismatch to wurtzite GaN. Within the modern theory of polarization, ScN has a nonvanishing formal polarization along the [111] direction. As a result, we demonstrate that an interface…

Materials Science · Physics 2019-12-23 Nicholas L. Adamski , Cyrus E. Dreyer , Chris G. Van de Walle

Nitrogen-polar III-nitride heterostructures offer advantages over metal-polar structures in high frequency and high power applications. However, polarity control in III-nitrides is difficult to achieve as a result of unintentional polarity…

An undoped AlGaN/GaN nanowire demonstrated p-type conductivity based solely on the formation of hole carriers in response to the negative polarization field at the (000-1) AlGaN/GaN facet. A transistor based on this nanowire displayed a…

Macroscopic polarization plays a major role in determining the optical and electrical properties of nitride nanostructures via polarization-induced built-in electrostatic fields. While currently fashionable, this field of endeavour is still…

Materials Science · Physics 2015-06-25 Fabio Bernardini , Vincenzo Fiorentini

Relaxations at nonpolar surfaces of III-V compounds result from a competition between dehybridization and charge transfer. First principles calculations for the (110) and (10$\bar{1}$0) faces of zincblende and wurtzite AlN, GaN and InN…

Materials Science · Physics 2009-10-31 Alessio Filippetti , Vincenzo Fiorentini , Giancarlo Cappellini , Andrea Bosin

We present ab-initio studies of band offsets, formation energy, and stability of (100) heterojunctions between (Zn,Be)(Se,Te) zincblende compounds, and in particular of the lattice-matched BeTe/ZnSe interface. Equal band offsets are found…

Materials Science · Physics 2009-10-31 Fabio Bernardini , Maria Peressi , Vincenzo Fiorentini

Binary ferroelectric nitrides are promising materials for information technologies and power electronics. However, polarization switching in these materials is highly unusual. From the structural perspective, polarization reversal is…

The behaviour of the cross-sectional polarization field is explored for thin nanowires of barium titanate from first-principles calculations. Topological defects of different winding numbers have been obtained, beyond the known textures in…

Materials Science · Physics 2011-09-19 J. W. Hong , G. Catalan , D. N. Fang , Emilio Artacho , J. F. Scott

The spontaneous and piezoelectric polarizations of III-nitrides considerably affect the operation of various III-nitride-based devices. We report an ab initio study of the spontaneous polarization (SP) and piezoelectric (PZ) constants of…

Applied Physics · Physics 2020-01-14 Kaikai Liu , Xiaohang Li

The integration of ferroelectric nitride thin films such as Al1-xScxN onto GaN templates could enable enhanced functionality in novel high-power transistors and memory devices. This requires a detailed understanding of the ferroelectric…

The discovery of wurtzite ferroelectrics opens new frontiers in polar materials, yet their behavior at cryogenic temperatures remains unexplored. Here, we reveal unprecedented ferroelectric properties in ultrathin (10 nm)…

We present a study of the polarization properties of emission lines from single InGaN/GaN quantum dots (QDs). The QDs, formed by spinodal decomposition within ultra-thin InGaN quantum wells, are investigated using single-QD…

Materials Science · Physics 2008-06-13 M. Winkelnkemper , R. Seguin , S. Rodt , A. Schliwa , L. Reissmann , A. Strittmatter , A. Hoffmann , D. Bimberg

We perform a first principles investigation of Si/ZnS interface properties for the [111], [100], and [110] directions, including single-substitution polar-compensated interfaces. The asymmetry of general interface directions poses known…

Materials Science · Physics 2014-10-13 David H. Foster , Guenter Schneider

Accurate values for polarization discontinuities between pyroelectric materials are critical for understanding and designing the electronic properties of heterostructures. For wurtzite materials, the zincblende structure has been used in…

Materials Science · Physics 2018-04-17 Cyrus E. Dreyer , Anderson Janotti , Chris G. Van de Walle , David Vanderbilt
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