High Precision Quantum Control of Single Donor Spins in Silicon
14 Jan 2008 | Papers | Contributor(s): Rajib Rahman, marta prada, Gerhard Klimeck, Lloyd Hollenberg
The Stark shift of the hyperfine coupling constant is investigated for a P donor in Si far below the ionization regime in the presence of interfaces using tight-binding and band minima basis approaches and compared to the recent precision measurements. In contrast with previous effective mass-based results, the quadratic Stark coefficient obtained from both theories agrees closely with the experiments. It is also shown that there is a significant linear Stark effect for an impurity near the ...
Valley splitting in strained silicon quantum wells modeled with 2 degree miscuts, step disorder, and alloy disorder
14 Jan 2008 | Papers | Contributor(s): Neerav Kharche, marta prada, Timothy Boykin, Gerhard Klimeck
Valley splitting (VS) in strained SiGe/Si/SiGe quantum wells grown on (001) and 2° miscut substrates is computed in a magnetic field. Calculations of flat structures significantly overestimate, while calculations of perfectly ordered structures underestimate experimentally observed VS. Step disorder and confinement alloy disorder raise the VS to the experimentally observed levels. Atomistic alloy disorder is identified as the critical physics, which cannot be modeled with analytical effective ...
Atomistic Simulation of Realistically Sized Nanodevices Using NEMO 3-D—Part II: Applications
14 Jan 2008 | Papers | Contributor(s): Gerhard Klimeck, Shaikh S. Ahmed, Neerav Kharche, Marek Korkusinski, Muhammad Usman, marta prada, Timothy Boykin
In part I, the development and deployment of a general nanoelectronic modeling tool (NEMO 3-D) has been discussed. Based on the atomistic valence-force field and the sp3d5s* nearest neighbor tight-binding models, NEMO 3-D enables the computation of strain and electronic structure in nanostructures consisting of more than 64 and 52 million atoms, corresponding to volumes of (110 nm)3 and (101 nm)3, respectively. In this part, successful applications of NEMO 3-D are demonstrated in the atomistic ...
Atomistic Simulation of Realistically Sized Nanodevices Using NEMO 3-D: Part I − Models and Benchmarks
14 Jan 2008 | Papers | 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 the underlying material are important. Approaches based on a continuum representation of the underlying material typically used by device engineers and physicists become invalid. Ab initio methods used ...