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Research

Mechanics & Physics of Heterogeneous Materials
Our research interests lie at the intersection of mechanics, computational materials science, and solid state physics. We integrate a blend of classical and quantum mechanical methods to uncover atomistic mechanisms that govern structural and electronic properties of solids and heterogeneous materialsOur objective is to understand fundamental mechanisms at the atomistic scales and apply the understanding to guide macroscopic design of materials and structures with new or improved functionalities.


A. Nanomechanics of brittle fracture 
Fracture is a prevalent failure mode in structural composites, aerospace structures, multi-junction solar cells, high temperature thermoelectrics, thermophotovoltaics, and battery. While successes in the field of fracture mechanics are impressive, it is also impressive how much remains unknown particularly at the nanoscale under heterogeneous conditions. Our effort focuses understanding the atomistic basis of crack nucleation and propagation without invoking any ad hoc criteria for prescribing nucleation or a possible crack-path. Current investigations include predicting crack nucleation and determining deflection-penetration criteria in non-linearly elastic brittle materials and their composites (involving 2D materials, nanotubes, carbide/nitride nanowires, van der Waals heterostructures). The images below show the onset of crack-nucleation in SiC nanowire and hexagonal boron nitride, respectively. For further information please see/follow our paper archive. Thanks for your interest! (People involved/contributed: Hao, Ben, Colin, Chris, Allison, Joe, Fazle, Tousif, Tianyi, Ling, Venkat, Zubaer). 
 



B. Mechanics of electron confinement in alloy quantum dots
We are investigating the role of mechanics in changing the way we look at enhancing efficiency in energy absorption and conversion materials -- such as solar cells and thermoelectric generators. Our aim is to understand energy absorption mechanisms in alloy-quantum-dot (AQD) thin film heterostructures and to construct new design principles for the integration of AQDs in photovoltaics and thermoelectric generators. Currently we are building multiscale computational methods coupling multiple atomistic and electronic structure methods to investigate effect of deformational and compositional heterogeneity on localization of electronic states in thermodynamically stable alloy quantum-dot based heterostructures. The image below shows a few basic confinement states in an isolated quantum dot. We seek to understand their interactions mediated by deformation induced elastic fields. For further information please see/follow our paper archive. Thanks for your interest! (People involved/contributed: Jinye, Millie, Shawn, Tianyi, Ben, Zubaer). 

 


C. Quantum mechanics at finite deformation 
Low-dimensional materials such as graphene or carbon nanotube show remarkable promise for next generation electronics, structural materials, energy, and biology. Nonetheless, due to lack of structural stability they are highly susceptible to undergo mechanical deformation, which alters their pristine properties substantially, particularly in the vicinity of insulating substrates on which they are grown, electrodes that they are attached to, or the external reactive molecules they are exposed during operationsIn order to predict mechanistic mechanisms that cause alteration of the electronic behavior, we investigate the implications of finite deformation using a combination of ab initio methods. The image below shows deformation induced electron density and bond deformation in a 2D material. For further information please watch out our recent papers. For further information please see/follow our paper archive. Thanks for your interest! (People involved/contributed: Zubaer).