Dr. Lawrence Friedman

Research Interests

Nanomechanical Modeling and Simulation:

• Continuum, Multiscale and Stochastic methods
• Nanoscale Pattern Formation / Self-Assembly
• Stress and Strain in Nanostructures and Nanostructured Materials
  

Areas of Application:

• Nanomechanical Standards for Atomic Force Microscopy
• Simulation of Self-Assembled Quantum Dot formation
• Energy of surfaces and internal interfaces
• Nanoindentation and Nanomechanical Measurement

Research Opportunity in Nanoscale Randomness in Surfaces and Solid Defects:

Much of nanotechnology and nanoscience is  devoted to the fabrication, control and analysis of surfaces and solid defects. The nucleation, growth and evolution of nanoscale defects and structures stands at the nexus of Materials Engineering, Mechanics and Statistical Physics. Nanoscale science in this area requires the solution to fundamental and technical questions such as “When is a collection of atoms just a collection of atoms, and when is it material?” or its more applied cousin, “How can we quantitatively describe the behavior of nanoscale materials and structures taking into account their atomic makeup and bonding?” Although of fundamental scientific importance, answering these questions and developing techniques will provide the quantitative tools necessary to define the next generation of nanoscale measurements and facilitate the design and optimization of the next generation of nanotechnology.  These studies will look at fluctuating motion and material evolution to create quantitatively accurate statistical models usable in materials analysis and design, focusing on nanoscale randomness and fluctuations as entities to be modeled and measured.  Areas of application include nanoscale self-assembly such as the famed self-assembled quantum dots, strained films and film growth, solid solution intermixing, stress-assisted nucleation of crystal defects and free energies of fracture surfaces. 

Keywords: films, defects, nanomechanics, self-assembly, modeling, materials theory

Please contact contact me if you are interested in discussing this research opportunity.

Selected Recent Publications Prior to Joining NIST

• Lei Fang and Christopher L. Muhlstein and James G. Collins and Amber L. Romasco and Lawrence H. Friedman. “Continuous electrical in situ contact area measurement during instrumented indentation. Journal of Materials Research. 23(9): 2480-2485 (2008).[DOI: 10.1557/JMR.2008.0298]

• L. H. Friedman, Surface Energy Effects on the Self-Assembly of Epitaxial Quantum Dots, Proc. SPIE, Vol. 7224, 722405 (Feb. 13, 2009).[DOI:10.1117/12.809796]

• L. H. Friedman, Stochastic continuum modeling self-assembled epitaxial quantum dot formation. Proc. SPIE, Vol. 7041, 704103 (2008) [DOI:10.1117/12.795615]

• L. H. Friedman, Anisotropy and Morphology of Strained III-V Heteroepitaxial Films, Physical Review B, 78, 193302 (4 pages) (2008). [DOI:10.1103/PhysRevB.78.193302]

• Chandan Kumar and Lawrence H. Friedman, Effects of elastic heterogeneity and anisotropy on the morphology of self-assembled epitaxial quantum dots Journal of Applied Physics, 104, 034902 (2008). [DOI:10.1063/1.2960560]