Positions open: We may
have positions for postdoc fellows, graduate students, and
undergraduate students. Please check
11/2018: Invited talk.
Dr. Ruan gave an invited talk at ASME IMECE.
10/2018: Student award.
Xiangyu received the third-place Best Poster Award at the
2018 CTRC Fall Meeting. Congratulations to Xiangyu!
09/2018: M.S. thesis
defense. Dedeepya successfully defended her M.S. thesis.
08/2018: Student award.
Jacob Faulkner joined our
group as an MS student and receives the Lozar Fellowship
from the School of Mechanical Engineering.
08/2018: Student award.
Luis Delgado joined our
group as a Ph.D. student and receives the Carver Fellowship
08/2018: Welcome New
Students. Luis Delgado, Jacob Faulkner, and Peiyan Yao have joined our group. Welcome!
Sustainable energy and thermal
management are among the greatest challenges facing the
society, and heat transfer researchers can
contribute. Solutions to these challenges rely on
extraordinarily fundamental and innovative approaches. In
our lab, we are developing renewable
energy technologies and thermal management solutions for
electronics using the emerging nanotechnology.
The behavior of all energy
systems can be related to atomic-scale description. With an
atomic-level knowledge of the thermal energy carriers
(photon, electron, phonon, and fluid particle), one is able
to design nano- and micro-structures with the desired size
effects, or to synthesize new materials with the desired
functionalities. Our lab is building and expanding the
understanding of the fundamentals of atomic-level carrier
transport and interactions, and is applying this knowledge
to important applications for energy efficiency and
electronics thermal management technologies.
Current projects fall in two
nanoscale heat conduction, and nano-photonics (including
nanoscale thermal radiation). Projects in the nanoscale
heat conduction (or nano-phononics) category include: (1)
high-performance nanostructured thermoelectric materials for
power generation and thermoelectric refrigeration; (2)
thermal transport and thermal rectification in carbon
nanotube and graphene for electronic thermal management
applications; (3) thermal interface resistance across CNT
(or graphene)-metal interfaces for electronic thermal
management applications. Projects in the nano-photonics
category include: (4) Suppression of electron-phonon
coupling in quantum dot solar cell materials for enhanced
efficiency; (5) Enhanced optical absorption in silicon
nanowire arrays for potentially enhanced solar cell
efficiency; (6) Multiscale control of thermal radiation in
ordered array of carbon nanotubes; (7) enhanced laser
cooling of semiconductors and ion-doped solids.
These projects involve
theoretical, computational, and experimental components.
Currently our lab devotes 2/3 efforts to theoretical and
simulation studies, and 1/3 effort to experimental work.
Theoretical tools include heat transfer, materials science,
quantum mechanics, solid state physics, optics, and
electromagnetic theory. Computational tools involve
multiscale simulation techniques of nanoscale energy
transport, including molecular dynamics simulations, first
principles calculations, Monte-Carlo simulations, and
Boltzmann transport theory. Experiments include fabrication
of nanomaterials and devices, and characterizations of these
materials and devices using advanced imaging and
spectroscopy techniques. Detailed information of our
research can be found
We have labs in both the ME
building and the
Birck Nanotechnology Center. We are also associated with
Energy Center at Purdue.
Most Recent Publications:
 T.L. Feng, Y. Zhong, J.J.
Shi, and X.L. Ruan, "Unexpected high inelastic phonon
transport across solid-solid interface: Modal nonequilibrium
molecular dynamics simulations and Landauer analysis," Phys.
Rev. B 99, 045301 (2019). [PDF]
 J. Peoples, X.Y. Li, Y
Lv, J Qiu, Z.F. Huang, and X.L. Ruan, "A strategy of
hierarchical particle sizes in nanoparticle composite for
enhancing solar reflection," Int. J. Heat Mass Trans. 131,
487-494 (2019). [PDF]
 T. Jiang, Z.Y. Wang, X.L.
Ruan, and Y. Zhu, "Equi-biaxial compressive strain in
graphene: Grüneisen parameter and buckling ridges," 2D
Materials 6, 015026 (2018) [PDF]
 L. Lindsay, C. Hua, X.L.
Ruan, and S. Lee, "Survey of ab initio phonon thermal
transport," Materials Today Physics 7, 106-120
 Z.X. Lu, A. Vallabhaneni,
B.Y. Cao, and X.L. Ruan, "Phonon branch-resolved
electron-phonon coupling and the multitemperature model,"
Phys. Rev. B 98, 134309 (2018). [PDF]
 T.L. Feng, X.L. Yang, and
X.L. Ruan, "Phonon anharmonic frequency shift induced by
four-phonon scattering calculated from first principles,"
J. Appl. Phys. 124, 145101 (2018). [PDF]
list of publications]