Structural and Electronic Properties of AlN, GaN And InN, and Band Offsets at AlN/GaN (1010) and (0001) Interfaces

1995 ◽  
Vol 395 ◽  
Author(s):  
A. Satta ◽  
Vincenzo Fiorentini ◽  
Andrea Bosin ◽  
F. Meloni ◽  
David Vanderbilt
Keyword(s):  
Density Functional ◽  
Structural Transition ◽  
Local Density ◽  
Plane Waves ◽  
Growth Direction ◽  
Band Offset ◽  
Valence Band Offset ◽  
Structural And Electronic Properties ◽  
Local Density Functional ◽  
Macroscopic Polarization

ABSTRACTAb initio local-density-functional calculations are presented for bulk A1N, GaN, and InN in the wurtzite, zincblende, and rocksalt structures. Structural transition pressures and deformation potentials of electronic gaps are investigated. In addition, we study the band offset at the polar (0001) and non-polar (1010) AIN/GaN interfaces. Within AIN-on-GaN epitaxial conditions, we obtain valence-band offset values close to 0.7 eV for both interfaces. From the macroscopic field appearing along the growth direction of the polar interface (tentatively attributed to AIN macroscopic polarization), an estimate of the macroscopic dielectric constant of GaN is extracted. All calculations employed conjugate-gradient total-energy minimizations, ultrasoft pseudopotentials, and plane waves at 25 Ryd cutoff.

Effect of Strain and Interface Interdiffusion on the Valence Band Offset at Si/Ge Interfaces

1989 ◽  
Vol 148 ◽  
Author(s):  
Mark S. Hybertsen
Keyword(s):  
Valence Band ◽  
Density Functional ◽  
Local Density ◽  
Interface Layer ◽  
Band Offset ◽  
Valence Band Offset ◽  
Interface Dipole ◽  
Strain Parameter ◽  
Interface Unit ◽  
Abrupt Interface

ABSTRACTThe valence band offset for the Si/Ge interface is studied using the local density functional approach with a superlattice geometry. The effect of non-abrupt interfaces is modeled by including an interface layer of Si5 Ge0 5 ordered in a interface unit cell. The change in valence band offset is less than 0.01 eV. For an abrupt interface, the offset is found to be a function of strain in the Ge. The interface dipole is proportional to the perpendicular strain parameter which yields an interface contribution to the energy of the strained epitaxial Ge layers. The equilibrium strain parameter in epitaxial Ge differs from that in biaxially compressed bulk Ge.

Formation Energy, Stress, and Relaxations of Low-Index Rhodium Surfaces

1995 ◽  
Vol 408 ◽  
Author(s):  
Alessio Filippetti ◽  
Vincenzo Fiorentini ◽  
Kurt Stokbro ◽  
Riccardo Valente ◽  
Stefano Baroni
Keyword(s):  
Density Functional ◽  
Parallel Implementation ◽  
Local Density ◽  
Plane Waves ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Energy Stress ◽  
Local Density Functional Theory ◽  
Local Density Functional ◽  
Formation Energies

AbstractAb initio local-density- functional- theory calculations of formation energies, surface stress, and multilayer relaxations are reported for the (111), (100), and (110) surfaces of Rh. The study is performed using ultrasoft pseudopotentials and plane waves in a parallel implementation.

Magnetic Properties of Embedded Rh Clusters in Ni Matrix

1995 ◽  
Vol 384 ◽  
Author(s):  
Zhi-Qiang Li ◽  
Yuichi Hashi ◽  
Jing-Zhi Yu ◽  
Kaoru Ohno ◽  
Yoshiyuki Kawazoe
Keyword(s):  
Magnetic Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Magnetic Moments ◽  
Functional Formalism ◽  
Rhodium Clusters ◽  
Spin Polarized ◽  
Local Density Functional

ABSTRACTThe electronic structure and magnetic properties of rhodium clusters with sizes of 1 - 43 atoms embedded in the nickel host are studied by the first-principles spin-polarized calculations within the local density functional formalism. Single Rh atom in Ni matrix is found to have magnetic moment of 0.45μB. Rh13 and Rhl 9 clusters in Ni matrix have lower magnetic moments compared with the free ones. The most interesting finding is tha.t Rh43 cluster, which is bulk-like nonmagnetic in vacuum, becomes ferromagnetic when embedded in the nickel host.

STRUCTURAL TRANSITIONS OF BiI3 UNDER PRESSURE

2012 ◽  
Vol 26 (32) ◽  
pp. 1250217
Author(s):  
XIAO-XIAO SUN ◽  
ZHI-RU REN ◽  
DAO-GUANG WANG
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Structural Transition ◽  
High Pressures ◽  
Functional Theory ◽  
High Pressure Studies ◽  
Volume Collapse ◽  
Pseudopotential Calculations ◽  
Structural And Electronic Properties ◽  
Pnma Phase

High pressure studies of BiI 3 at 0 K are performed using first-principles pseudopotential calculations within the framework of density functional theory. The calculations indicate that BiI 3 undergoes a structural transition from rhombohedral R-3 phase to monoclinic P2 1/c phase at 7 GPa which is accompanied by a 5.8% volume collapse. In addition, we find that P2 1/c phase prevails about 60 GPa range and transforms to cubic Fm-3m phase at 68 GPa, and finally takes the orthorhombic Pnma phase at high pressures up to 133 GPa. The structural and electronic properties of four competitive structures are also calculated. The analysis of density of states reveals that BiI 3 has semiconductor-metal transition at about 61 GPa, which also demonstrates the metallic nature of both Fm-3m and Pnma phases.

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