title: Blocking Phonon Transport by Structural Resonances in Alloy-Based Nanophononic Metamaterials Leads to Ultralow Thermal Conductivity.
abstract: Understanding the design rules to obtain materials that enable a tight control of phonon transport over a broad range of frequencies would aid major developments in thermoelectric energy harvesting, heat management in microelectronics, and information and communication technology. Using atomistic simulations we show that the metamaterials approach relying on localized resonances is very promising to engineer heat transport at the nanoscale. Combining designed resonant structures to alloying can lead to extremely low thermal conductivity in silicon nanowires. The hybridization between resonant phonons and propagating modes greatly reduces the group velocities and the phonon mean free paths in the low frequency acoustic range below 4 THz. Concurrently, alloy scattering hinders the propagation of high frequency thermal phonons. Our calculations establish a rationale between the size, shape, and period of the resonant structures, and the thermal conductivity of the nanowire, and demonstrate that this approach is even effective to block phonon transport in wavelengths much longer than the size and period of the surface resonant structures. A further consequence of using resonant structures is that they are not expected to scatter electrons, which is beneficial for thermoelectric applications.
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, 55218 Mainz, Germany.|CNRS, UPR 288 Laboratoire d'Energétique Moléculaire et Macroscopique, Combustion (EM2C), Ecole Centrale Paris, Grande Voie des Vignes, 92295 Châtenay-Malabry, France.
authors.forename: Shiyun
authors.initials: S
authors.lastname: Xiong
authors.affiliation: Engineered Nanosystems group, School of Science, Aalto University, P.O. Box 12200, 00076 Aalto, Finland.
authors.forename: Kimmo
authors.initials: K
authors.lastname: Sääskilahti
authors.affiliation: CNRS, UPR 288 Laboratoire d'Energétique Moléculaire et Macroscopique, Combustion (EM2C), Ecole Centrale Paris, Grande Voie des Vignes, 92295 Châtenay-Malabry, France.|Semenov Institute of Chemical Physics, Russian Academy of Sciences, 119991 Moscow, Russia.
authors.forename: Yuriy A
authors.initials: YA
authors.lastname: Kosevich
authors.affiliation: CNRS, UPR 288 Laboratoire d'Energétique Moléculaire et Macroscopique, Combustion (EM2C), Ecole Centrale Paris, Grande Voie des Vignes, 92295 Châtenay-Malabry, France.
authors.forename: Haoxue
authors.initials: H
authors.lastname: Han
authors.affiliation: Department of Chemistry, University of California Davis, One Shields Avenue, Davis, California 95616, USA.
authors.forename: Davide
authors.initials: D
authors.lastname: Donadio
authors.affiliation: CNRS, UPR 288 Laboratoire d'Energétique Moléculaire et Macroscopique, Combustion (EM2C), Ecole Centrale Paris, Grande Voie des Vignes, 92295 Châtenay-Malabry, France.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Volz