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Machine learned approximations to Density Functional Theory Hamiltonians - Towards High-Throughput Screening of Electronic Structure and Transport in Materials
13 Dec 2016 | | Contributor(s):: Ganesh Krishna Hegde
We present results from our recent work on direct machine learning of DFT Hamiltonians. We show that approximating DFT Hamiltonians accurately by direct learning is feasible and compare them to existing semi-empirical approaches to the problem. The technique we have proposed requires little...
[Illinois] Peptide Release from the Cells of the Dorsal Root Ganglion upon Application of Tensile Strain
04 Feb 2014 | | Contributor(s):: Emily Tillmaand
Morphological and electrophysiological studies have shown that neurons respond to specific mechanical environments. However, studies linking specific neuropeptide release based on changes in the mechanical environment are lacking. To further study the effect of mechanical stress on the cells of...
Structure and Morphology of Silicon Germanium Thin Films
30 Dec 2013 | | Contributor(s):: Brian Demczyk
Single layer silicon and germanium films as well as nominally 50-50 silicon-germanium alloys were deposited on single crystal silicon and germanium (001) and (111) substrates by ultrahigh vacuum chemical vapor deposition. These films spanned the range of + 4 % film-substrate lattice mismatch. A...
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GaAs with biaxial strain, swept from -3% to +3% produces the following error:
Problem launching job: Program...
Why quantum dot simulation domain must contain multi-million atoms?
11 Jan 2013 | | Contributor(s):: Muhammad Usman
The InGaAs quantum dots obtained from the self-assembly growth process are heavily strained. The long-range strain and piezoelectric fields significantly modifies the electronic structure of the quantum dots. This imposes a critical constraint on the minimum size of the simulation domain to...
Excited State Spectroscopy of a Quantum Dot Molecule
Atomistic electronic structure calculations are performed to study the coherent inter-dot couplings of the electronic states in a single InGaAs quantum dot molecule. The experimentally observed excitonic spectrum by Krenner et al (Phys. Rev. Lett. 94 057402, 2005) is quantitatively reproduced,...
NEMO5 Tutorial 5C: Quantum Dots with Strain and Electronic Wave Functions
18 Jul 2012 | | Contributor(s):: Yuling Hsueh
NEMO5 Tutorial 5B: Strain
18 Jul 2012 | | Contributor(s):: Hesameddin Ilatikhameneh
Learn how the NEMO5 strain solver works.
NEMO5 Overview Presentation
17 Jul 2012 | | Contributor(s):: Tillmann Christoph Kubis, Michael Povolotskyi, Jean Michel D Sellier, James Fonseca, Gerhard Klimeck
This presentation gives an overview of the current functionality of NEMO5.
Polarization Response of Multi-layer InAs Quantum Dot Stacks
25 Oct 2011 | | Contributor(s):: Muhammad Usman
Recent experimental measurements, without any theoretical guidance, showed that isotropic polarization response can be achieved by increasing the number of QD layers in a QD stack. In this work, we analyse the polarization response of multi-layer quantum dot stacks containing up to nine quantum...
Experiments and Models Regarding Strain Dependent Thermal Conductivity and Strength at the Nanoscale and Microscale
22 Sep 2011 | | Contributor(s):: Vikas Tomar
Silicon micro- and nano-structures are essential in today’s integrated circuits and sensors. The functioning and performance of such devices are highly affected by thermal properties. Due to the size effect, the thermal properties of bulk silicon cannot represent those of silicon...
Quantitative Modeling and Simulation of Quantum Dots
18 Apr 2011 | | Contributor(s):: Muhammad Usman
Quantum dots grown by self-assembly process are typically constructed by 50,000 to 5,000,000 structural atoms which confine a small, countable number of extra electrons or holes in a space that is comparable in size to the electron wavelength. Under such conditions quantum dots can be...
Coupled Effect of Strain and Magnetic Field on Electronic Bandstructure of Graphene
07 Dec 2010 | | Contributor(s):: yashudeep singh
We explore the possibility of coupling between planar strain and perpendicular magnetic field on electronic bandstructure of graphene. We study uni-axially, bi-axially and shear strained graphene under magnetic field. In line with Rammal’s formalism using nearest neighbor tight binding scheme we...
Nanoelectronic Modeling Lecture 32: Strain Layer Design through Quantum Dot TCAD
04 Aug 2010 | | Contributor(s):: Gerhard Klimeck, Muhammad Usman
This presentation demonstrates the utilization of NEMO3D to understand complex experimental data of embedded InAs quantum dots that are selectively overgrown with a strain reducing InGaAs layer. Different alloy concentrations of the strain layer tune the optical emission and absorption...
InAs: Evolution of iso-energy surfaces for heavy, light, and split-off holes due to uniaxial strain.
25 May 2010 | | Contributor(s):: Abhijeet Paul, Denis Areshkin, Gerhard Klimeck
Movie was generated using Band Structure Lab tool at nanoHUB and allows to scan over four parameters:Hole energy measured from the top of the corresponding band (i.e. the origin of energy scales for LH and SOH is different)Strain direction: , , Carrier type: LH, HH, SOHStrain...
Universality of NBTI-Induced Interface Trap Generation and Its Impact on ID Degradation in Strained/ Unstrained PMOS Transistors
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23 Dec 2008 | | Contributor(s):: Ahmad Ehteshamul Islam, Muhammad A. Alam
Despite extensive use of strained technology, it is still unclear whether NBTI-induced NIT generation in strained transistors is substantially different from that of unstrained ones. Here, we present a comprehensive theory for NIT generation in strained/unstrained transistors and show its...
Atomistic Simulation of Realistically Sized Nanodevices Using NEMO 3-D: Part I - Models and Benchmarks
14 Jan 2008 | | Contributor(s):: Gerhard Klimeck, Shaikh S. Ahmed, Neerav Kharche, Hansang Bae, Steven Clark, Benjamin P Haley, Maxim Naumov, Hoon Ryu, Faisal Saied, marta prada, Marek Korkusinski, Timothy Boykin
Device physics and material science meet at the atomic scale of novel nanostructured semiconductors, and the distinction between new device or new material is blurred. Not only the quantum-mechanical effects in the electronic states of the device but also the granular atomistic representation of...