Table Of ContentSpringerSeriesin
materials science
93
SpringerSeriesin
materials science
Editors: R.Hull R.M.Osgood,Jr. J.Parisi H.Warlimont
The Springer Series in Materials Science covers the complete spectrum of materials physics,
includingfundamentalprinciples,physicalproperties,materialstheoryanddesign.Recognizing
theincreasingimportanceofmaterialsscienceinfuturedevicetechnologies,thebooktitlesinthis
seriesreflectthestate-of-the-artinunderstandingandcontrollingthestructureandproperties
ofallimportantclassesofmaterials.
76 SpirallyAnisotropicComposites 85 LifetimeSpectroscopy
ByG.E.Freger,V.N.Kestelman, AMethodofDefectCharacterization
andD.G.Freger inSiliconforPhotovoltaicApplications
ByS.Rein
77 ImpuritiesConfined
inQuantumStructures 86 Wide-GapChalcopyrites
ByP.O.HoltzandQ.X.Zhao Editors:S.SiebentrittandU.Rau
78 MacromolecularNanostructured 87 Micro-andNanostructuredGlasses
Materials ByD.Hülsenberg,A.Harnisch,
Editors:N.UeyamaandA.Harada andA.Bismarck
79 MagnetismandStructure 88 IntroductiontoWaveScattering,
inFunctionalMaterials LocalizationandMesoscopicPhenomena
Editors:A.Planes,L.Mano˜sa, ByP.Sheng
andA.Saxena
89 Magnetoscience
80 IonImplantation MagneticFieldEffectsonMaterials:
andSynthesisofMaterials FundamentalsandApplications
ByM.NastasiandJ.W.Mayer Editors:M.YamaguchiandY.Tanimoto
81 MetallopolymerNanocomposites 90 InternalFrictioninMetallicMaterials
ByA.D.PomogailoandV.N.Kestelman AReferenceBook
ByM.S.Blanter
82 PlasticsforCorrosionInhibition
ByV.A.Goldade,L.S.Pinchuk, 91 Time-dependentMechanicalProperties
A.V.MakarevichandV.N.Kestelman ofSolidBodies
ATheoreticalApproach
83 SpectroscopicProperties ofRareEarths
ByW.Gräfe
inOpticalMaterials
Editors:G.LiuandB.Jacquier 92 SolderJointTechnology
Materials,Properties,andReliability
84 Hartree–Fock–SlaterMethod
ByK.N.Tu
forMaterialsScience
TheDV–XAlphaMethodforDesign 93 MaterialsforTomorrow
andCharacterizationofMaterials Theory,ExperimentsandModelling
Editors:H.Adachi,T.Mukoyama, Editors:S.Gemming,M.Schreiber,
andJ.Kawai andJ-B.Suck
Volumes25–75arelistedattheendofthebook.
· ·
S. Gemming M. Schreiber J.-B. Suck
(Eds.)
Materials
for Tomorrow
Theory, Experiments and Modelling
With92Figures,7inColour
123
PDDr.SibylleGemming Prof.Dr.Jens-BoieSuck
InstituteofIonBeamPhysics InstituteofPhysics
andMaterialsResearch UniversityofTechnologyChemnitz
ForschungszentrumDresden-Rossendorfe.V. ReichenhainerStraße70
PF510119 D-09107Chemnitz,Germany
D-01314Dresden,Germany E-mail:[email protected]
E-Mail:[email protected]
Prof.Dr.MichaelSchreiber
InstituteofPhysics
UniversityofTechnologyChemnitz
ReichenhainerStraße70
D-09107Chemnitz,Germany
E-mail:[email protected]
SeriesEditors:
ProfessorRobertHull ProfessorJürgenParisi
UniversityofVirginia UniversitätOldenburg,FachbereichPhysik
Dept.ofMaterialsScienceandEngineering Abt.Energie-undHalbleiterforschung
ThorntonHall Carl-von-Ossietzky-Strasse9–11
Charlottesville,VA22903-2442,USA 26129Oldenburg,Germany
ProfessorR.M.Osgood,Jr. ProfessorHansWarlimont
MicroelectronicsScienceLaboratory InstitutfürFestkörper-
DepartmentofElectricalEngineering undWerkstofforschung,
ColumbiaUniversity Helmholtzstrasse20
SeeleyW.MuddBuilding 01069Dresden,Germany
NewYork,NY10027,USA
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Preface
Materials science has assumed a key position for new technological devel-
opments, and is therefore strongly supported by industry and governments.
Nowadays it occupies a bridging position between physics, chemistry and en-
gineering and extends from basic science in physics and chemistry on the
atomic scale to large-scale applications in industry. The increasing number
of materials science study courses at universities underlines the present and
future importance of understanding and developing materials for the future.
The contributions to this book evolved from the lectures of such a course,
namely the Heraeus summer school on “New Materials for Today, Tomorrow
and Beyond”, held at Chemnitz University of Technology in October 2004.
Looking at the rapidly developing communications industry, it is obvious
that a large part of current research for future materials is devoted to the
understanding of materials to be used in nanometer (nm) scale devices. It is
therefore not surprising that five of the six lectures collected in this volume
aredevotedmoreorlessdirectlytothenmscale,whilethefirstonetreatsone
ofthecentralunsolvedproblemsofcondensedmatterphysicsand–becauseof
thewidespreadindustrialapplicationofglassesineverydaylife–touchingalso
materialsscience.Someofthematerialsdiscussedherearealreadyusedtoday,
for others the development has proceeded far enough that their application
can be expected in the near future. Yet others,however,we will not be ready
to use until some years from now, assuming that the difficulties connected
with their application are solved in the near future.
Theabove-mentionedfirstarticle,writtenby oneofthe bestknownscien-
tists in the field of computer simulations, introduces the molecular dynamics
(MD) methods used in the calculation of the structure and atomic-scale dy-
namicsofnewmaterials.Themethodhasnowgainedanadmirablepredictive
power in materials science, explaining details not or hardly accessible by ex-
periments. This has become possible through ab initio calculations of the
electronic structure of the material using density functional theory (DFT),
which provide very realistic results. These can then be used to model the
force field, in which the atoms interact, for MD simulation of larger systems.
VI Preface
In this way undercooled silicate-based fluids and glasses have been success-
fully investigated including the as yet poorly understood transition from the
fluid to the glassy phase.
The same kind of technique was also used to investigate inorganic nano-
tubes. Carbonnanotubes (NT) have been at the centre of interest since their
discovery in 1991, followed by organic NT BxCyNz. Both of them are al-
ready used in many applications and will find more in the future. However,
since then dozens of other inorganic materials have been discovered, which
form NT as well. The starting materials are layered compounds, character-
ized by strong covalent bonds within the layers and van-der-Waals forces be-
tweenthem.Theirstructureisoftencomplicatedandtheirpropertiesnotwell
known, even though they have great application potential. Simulations of in-
organicNTarethereforepresentedinthe secondcontribution,withaviewto
better understanding the properties of these special NT.
Nanotechnologyalsoplaysa decisiveroleininformationtechnology.How-
ever,therapidincrease(doublingoftheInternettrafficevery6months,ofthe
wireless capacities every 9 months and of the magnetic information storage
every15months)cannotbecompensatedbyacorrespondingshrinkageofthe
semiconductordevices,asitwasachievedinthepast30years.Tokeepupwith
the demands, completely new devices have to be invented, operating on the
nanoscaleandexploitingquantumeffects.Onepossibilityis tousethespinof
the electron in addition to its charge for information transmission and stor-
age, i.e. going from conventional electronics to spintronics. The foundations
of this technique, exploiting the giant magnetoresistance and the tunneling
magnetoresistance are discussed from the experimental and theoretical point
of view in the third contribution.
Interfaces play a very important role for the stability and functioning
of materials, sometimes as barriers, sometimes mediating between adjacent
grains or layers, sometimes protecting the material next to them, avoiding
overheatingorcorrosionineverydaymaterials.Homophase(betweentwoma-
terials of the same chemical composition and atomic structure) grain bound-
aries (GB) and heterophase (between two chemically or structurally different
materials) interfaces are discussed from a theoretical point of view in the
fourth contribution. Electronic and atomic structures at planar GB and het-
erophase interfaces are investigated and classified according to the dominant
interaction determining their properties.
For many technical applications,the dimensions of semiconductor devices
are rapidly approachinglength scales at which a classical description of their
electronic structure and transport properties is insufficient and quantum ef-
fects must be taken into account. But since these devices are still too large
foranatomisticdescription,continuummodelswithempiricallyadjustedma-
terial parameters are successfully used to describe their properties. These
continuum models and their implementation in a simulation software are de-
scribed in the fifth contribution.
Preface VII
When working with devices on the nanoscale one necessarily runs into
theproblemthatsomephysicallysignificantlengths,likeacorrelationlength,
a screening length, the mean free path, etc. start to exceed the dimension of
the devices. This necessarily leads to a drastic change of the physical proper-
ties in comparison to those in the same material at larger dimensions. Such
achangeofpropertieswithrespecttothemeltingtemperature,magneticand
mechanical properties and finally to the atomic dynamics is discussed at the
example of metallic nanocrystals in the final contribution to this book.
As the lectures were given to students of different disciplines (physics,
chemistry,materialsscience),thearticlesdescribenotonlyourcurrentknowl-
edge in eachof the fields, but also basic facts needed for their understanding.
Thus the articles combine basic information at a textbook level with a pre-
sentation of cutting-edge research in the field and an outlook to future de-
velopments, thereby bridging the gap between specialized reviews and study
books.Inaddition,lecturesonmaterialssimulation,averyrapidlyadvancing
discipline, are combined with lectures on experimental research in materials
science, and the techniques used in both of these disciplines.
Theeditorsofthisbookareindebtedtothelecturersofthesummerschool
for taking on the burden of writing up their contributions in addition to
presentingthem. Finallywe wouldlike to thank the WE HeraeusStiftung for
enabling us to organize this school by its generous financial support.
Chemnitz, July 2006 Sibylle Gemming
Michael Schreiber
Jens-Boie Suck
Contents
1 Computer Simulations of Undercooled Fluids and Glasses
K. Binder, D. Herzbach, J. Horbach, M.H. Mu¨ser.................... 1
1.1 Introduction ............................................... 1
1.2 A Tutorial Review of the MD Technique....................... 4
1.2.1 The Verlet Algorithm ................................ 4
1.2.2 How to Estimate Intensive Thermodynamic Variables
from Microcanonical MD Runs;
Realization of Other Ensembles ....................... 7
1.2.3 Diffusion, Hydrodynamic Slowing Down, Einstein
and Green–Kubo Relations ........................... 9
1.3 A Comparative Test of Model Potentials for Silica .............. 12
1.4 Simulations of Molten and Glassy Silicon Dioxide............... 23
1.5 Mixtures of Silicon Dioxide with Sodium Oxide
and Aluminium Oxide....................................... 27
1.6 Conclusions................................................ 29
References ...................................................... 30
2 Simulation of Inorganic Nanotubes
A.N. Enyashin, S. Gemming, G. Seifert ............................ 33
2.1 Introduction ............................................... 33
2.2 Design of Inorganic Nanotubes ............................... 34
2.3 General Criteria for the Stability of Inorganic Nanotubes ........ 38
2.4 Theoretical Prediction of the Properties
of Non-Carbon Nanotubes ................................... 40
2.4.1 Nanotubes of the IVA Group Elements ................. 41
2.4.2 Nanotubes of the VA Group Elements.................. 43
2.4.3 Nanotubes of Boron and Borides ...................... 43
2.4.4 Nanotubes of Boron Nitride and its Analogues .......... 45
X Contents
2.4.5 Nanotubes of Chalcogenides .......................... 47
2.4.6 Nanotubes of Oxides................................. 50
2.5 Conclusion................................................. 54
References ...................................................... 55
3 Spintronics: Transport Phenomena
in Magnetic Nanostructures
P. Zahn ........................................................ 59
3.1 Introduction ............................................... 59
3.2 Magnetism in Nanostructures ................................ 61
3.2.1 Magnetism in Reduced Dimensions .................... 61
3.2.2 First Principals Calculational Scheme .................. 62
3.2.3 Magnetic Interlayer Exchange Coupling ................ 64
3.3 Transport Phenomena....................................... 66
3.3.1 Transport Theory ................................... 66
Diffusive and Coherent Transport Regime............... 67
Boltzmann Theory................................... 68
Residual Resistivity.................................. 69
Landauer Theory.................................... 70
3.3.2 Giant Magnetoresistance ............................. 72
Basics.............................................. 72
Microscopic Origin................................... 73
Applications ........................................ 77
3.3.3 Tunneling Magnetoresistance.......................... 78
Basics.............................................. 78
Microscopic Origin................................... 80
Applications ........................................ 85
References ...................................................... 86
4 Theoretical Investigation of Interfaces
S. Gemming, M. Schreiber ........................................ 91
4.1 Interfaces – Boundaries Between Two Phases................... 91
4.1.1 Introduction ........................................ 92
4.1.2 Interactions......................................... 95
Coulomb Interaction ................................. 95
Elastic Interaction ................................... 96
Electron Transfer.................................... 97
Pauli Repulsion ..................................... 98
Image Charge Interaction............................. 98
4.2 Theoretical Methods ........................................ 98
4.2.1 Theory of the Electronic Structure..................... 99
Density-Functional Theory............................ 99
Computational Details of Bulk State Calculations .......100
Density-Functional Tight-Binding Approaches ..........100
Contents XI
4.2.2 Classical Modelling ..................................101
Image-Charge Models ................................101
Effective Many-Body Potentials .......................102
Ionic Models ........................................103
4.3 Homophase Boundaries......................................104
4.3.1 Pristine Boundaries..................................105
4.3.2 Non-Stoichiometric and Doped Boundaries..............108
4.4 Heterophase Boundaries .....................................109
4.4.1 Wetting and Growth of Metal Layers...................110
4.4.2 Metal–Ceramic Boundaries ...........................112
4.4.3 Reactive Metal–Semiconductor Interfaces ...............116
4.5 Summary and Outlook ......................................118
References ......................................................119
5 Electronic Structure and Transport
for Nanoscale Device Simulation
A. Trellakis, P. Vogl..............................................123
5.1 Introduction ...............................................123
5.2 Electronic Structure of Semiconductors........................125
5.2.1 Bloch Theory and the Band Structure..................125
5.2.2 The k·p-Approximation ..............................127
5.2.3 Conduction and Valence Band Models..................128
5.3 Heterostructures............................................130
5.3.1 The Envelope Function Approximation.................130
5.3.2 Elastic Deformation and Strain........................131
5.3.3 Carrier Densities at Non-Zero Temperature .............132
5.3.4 Charge Distributions and the Poisson Equation..........134
5.4 Carrier Transport in Nanostructures ..........................135
5.4.1 Classical Ballistic Transport ..........................135
5.4.2 Scattering and the Boltzmann Equation ................136
5.4.3 The Drift-Diffusion Equations.........................138
5.4.4 Quantum Corrected Drift-Diffusion ....................139
5.4.5 Quantum Ballistic Transport..........................140
5.5 The nextnano3 Simulation Package ...........................141
5.5.1 Capabilities Overview ................................141
5.5.2 Numerical Methods ..................................142
5.5.3 Example Application.................................144
References ......................................................145
6 Metallic Nanocrystals and Their Dynamical Properties
Jens-Boie Suck ..................................................147
6.1 Introduction ...............................................147
6.2 Production of Nanocrystalline Materials .......................150
6.3 Characterization of Nanocrystalline Materials ..................155
