
Periodic Potentials and the KronigPenney Model
01 Jul 2008   Contributor(s):: Dragica Vasileska
This material describes the derivation of the KronigPenney model for deltafunction periodic potentials.

Periodic Potentials and Bandstructure: an Exercise
02 Jul 2008   Contributor(s):: Dragica Vasileska, Gerhard Klimeck
This exercise teaches the students that in the case of strong coupling between the neighboring wells in square and Coulomb periodic potential wells electrons start to behave as free electrons and the gaps that open at the Brillouin zone boundaries become smaller and smaller (thus recovering the...

Computational Nanoscience, Lecture 19: Band Structure and Some InClass Simulation: DFT for Solids
30 Apr 2008   Contributor(s):: Jeffrey C Grossman, Elif Ertekin
In this class we briefly review band structures and then spend most of our class on inclass simulations. Here we use the DFT for molecules and solids (Siesta) course toolkit. We cover a variety of solids, optimizing structures, testing kpoint convergence, computing cohesive energies, and...

What would be the electron effective mass of InAs in its electron valleys in X,Y,Z directions?
Open  Responses: 1
The default values in the Multi gate Nanowire tool for Si effective mass in Valley 1,2,3 in x,y,z directions are
0.19,0.19,0.98; 0.19,0.98,0.19; 0.98,0.19,0.19 respectively.
Now if i am going...
http://nanohub.org/answers/question/56

The Novel Nanostructures of Carbon
28 Feb 2008   Contributor(s):: Gene Dresselhaus
A brief review will be given of the physical underpinnings of carbon nanostructures that were developed over the past 60 years, starting with the electronic structure and physical properties of graphene and graphite, and then moving to graphite intercalation compounds which contained the first...

Computational Nanoscience, Lecture 4: Geometry Optimization and Seeing What You're Doing
13 Feb 2008   Contributor(s):: Jeffrey C Grossman, Elif Ertekin
In this lecture, we discuss various methods for finding the ground state structure of a given system by minimizing its energy. Derivative and nonderivative methods are discussed, as well as the importance of the starting guess and how to find or generate good initial structures. We also briefly...

Homework Assignment: Periodic Potentials
31 Jan 2008   Contributor(s):: David K. Ferry
Using the Periodic Potential Lab on nanoHUB determine the allowed bands for an energy barrier of 5 eV, a periodicity W = 0.5nm, and a barrier thickness of 0.1nm. How do these bands change if the barrier thickness is changed to 0.2 nm?

MIT AtomicScale Modeling Toolkit
15 Jan 2008   Contributor(s):: daniel richards, Elif Ertekin, Jeffrey C Grossman, David Strubbe, Justin Riley
Tools for AtomicScale Modeling

Engineering at the nanometer scale: Is it a new material or a new device?
06 Nov 2007   Contributor(s):: Gerhard Klimeck
This seminar will overview NEMO 3D simulation capabilities and its deployment on the nanoHUB as well as an overview of the nanoHUB impact on the community.

MCW07 Impact of Porphyrin Functional Groups on InAs Gas Sensors
05 Nov 2007   Contributor(s):: Michael Garcia
Porphyrin molecules are often used for sensor engineering to improve sensitivity and selectivity to specific analytes. It is important to understand how the porphyrin HOMOLUMO levels deplete surface states during functionalization of solid state sensors. Additionally, the effect of...

Simple Photonic Crystals
16 Aug 2007   Contributor(s):: Jing Ouyang, Xufeng Wang, Minghao Qi
Photonic Crystal characteristics in an easy way

MCW07 Electronic Level Alignment at MetalMolecule Contacts with a GW Approach
05 Sep 2007   Contributor(s):: Jeffrey B. Neaton
Most recent theoretical studies of electron transport in singlemolecule junctions rely on a Landauer approach, simplified to treat electronelectron interactions at a meanfield level within density functional theory (DFT). While this framework has proven relatively accurate for certain...

A Tutorial for Nanoelectronics Simulation Tools
03 Jul 2007   Contributor(s):: James K Fodor, Jing Guo
This learning module introduces nanoHUB users to some of the available simulators. The simulators discussed are FETToy, nanoMOS, Schred, CNTbands, and QDot Lab. For each simulator, a brief introduction to the simulator is presented, followed by voiced presentations featuring the simulator in...

Introduction to CNTbands
28 Jun 2007   Contributor(s):: James K Fodor, Jing Guo
This learning module introduces nanoHUB users to the CNTbands simulator. A brief introduction to CNTbands is presented, followed by voiced presentations featuring the simulator in action. Upon completion of this module, users should be able to use this simulator to gain valuable insight into the...

StrainBands
15 Jun 2007   Contributor(s):: Joe Ringgenberg, Joydeep Bhattacharjee, Jeffrey B. Neaton, Jeffrey C Grossman, Eric Schwegler
Explore the influence of strain on firstprinciples bandstructures of semiconductors.

Bandstructure of Carbon Nanotubes and Nanoribbons
14 Jun 2007   Contributor(s):: James K Fodor, Seokmin Hong, Jing Guo
This learning module introduces users to the CarbonNano Bands simulation tool, which simulates the bandstructure of Carbon Nanotubes (CNTs) and Nanoribbons (CNRs). To gives users a strong background in bandstructure, the module starts with sections that introduce bandstructure basics. To this...

Atomistic Alloy Disorder in Nanostructures
26 Feb 2007   Contributor(s):: Gerhard Klimeck
Electronic structure and quantum transport simulations are typically performed in perfectly ordered semiconductor structures. Bands and modes are defined resulting in quantized conduction and discrete states. But what if the material is fundamentally disordered? What if the disorder is at the...

Energy Bands In Periodic Potentials
11 Jan 2007   Contributor(s):: Heng Li
It is the KronigPenny Model.The particle in onedimensional lattice is a problem that occurs in the model of periodic crystal lattice.The potential is caused by periodic arrangement of ions in the crystal structure. The graph presents the real part of transmission matrix element P11 plotted...

Surprises on the nanoscale: Plasmonic waves that travel backward and spin birefringence without magnetic fields
08 Jan 2007 
As nanonphotonics and nanoelectronics are pushed down towards the molecular scale, interesting effects emerge. We discuss how birefringence (different propagation of two polarizations) is manifested and could be useful in the future for two systems: coherent plasmonic transport of nearfield...

CNTbands
14 Dec 2006   Contributor(s):: Gyungseon Seol, Youngki Yoon, James K Fodor, Jing Guo, Akira Matsudaira, Diego Kienle, Gengchiau Liang, Gerhard Klimeck, Mark Lundstrom, Ahmed Ibrahim Saeed
This tool simulates Ek and DOS of CNTs and graphene nanoribbons.