Ajit K. Vallabhaneni

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We show that thermal rectification (TR) in asymmetric graphene nanoribbons (GNRs) is originated from phonon confinement in the lateral dimension, which is a fundamentally new mechanism different from that in macroscopic heterojunctions. Our molecular dynamics simulations reveal that, though TR is significant in nanosized asymmetric GNRs, it diminishes at(More)
passivation and isotope engineering: A molecular dynamics study Jiuning Hu, Stephen Schiffli, Ajit Vallabhaneni, Xiulin Ruan, and Yong P. Chen School of Electrical and Computer Engineering, Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA School of Electrical and Computer Engineering, Purdue University, West Lafayette,(More)
graphene nanoribbons Jiuning Hu, 2, a) Yan Wang, Ajit Vallabhaneni, Xiulin Ruan, 2 and Yong P. Chen 2, 1, b) School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, USA Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA School of Mechanical Engineering, Purdue University, West(More)
This work examines the quality factors (Q factors) of resonance associated with the axial and transverse vibrations of single-wall carbon nanotube (SWCNT) resonators through the use of molecular dynamics (MD) simulation. Specifically, the work investigates the effect of device length, diameter, and chirality, as well as temperature, on the resonant(More)
The mean free paths (MFPs) of energy carriers are of critical importance to the nanoengineering of better thermoelectric materials. Despite significant progress in the first-principles– based understanding of the spectral distribution of phonon MFPs in recent years, the spectral distribution of electron MFPs remains unclear. In this work, we compute the(More)
carbon nanotube/graphene nanoribbon-silicon interfaces Ajit K. Vallabhaneni, Bo Qiu, Jiuning Hu, Yong P. Chen, Ajit K. Roy, and Xiulin Ruan School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, USA School of Electrical Computer Engineering, Purdue University, West Lafayette, Indiana 47907, USA Birck Nanotechnology Center,(More)
This article reviews recent numerical studies of thermal transport in graphene, with a focus on molecular dynamics simulation, the atomistic Green’s function method, and the phonon Boltzmann transport equation method. The mode-wise phonon contribution to the intrinsic thermal conductivity (κ) of graphene and the effects of extrinsic mechanisms—for example,(More)
We investigate the thermal rectification phenomena in asymmetric graphene and carbon nanotube systems using molecular dynamics (MD) simulations. The effects of various parameters, including mean temperature, temperature difference, and system size on rectification factor have been studied. In homogenous triangular graphene nanoribbons (TGNR), the heat(More)
The measured frequencies and intensities of different first- and second-order Raman peaks of suspended graphene are used to show that optical phonons and different acoustic phonon polarizations are driven out of local equilibrium inside a submicron laser spot. The experimental results are correlated with a first-principles-based multiple temperature model(More)
Hu, Jiuning Ph.D., Purdue University, May 2015. Transport studies in graphenebased materials and structures. Major Professor: Yong P. Chen. Graphene, a single atomic layer of graphite, has emerged as one of the most attractive materials in recent years for its many unique and excellent properties, inviting a broad area of fundamental studies and(More)