Ballistic heat

Apr 21, 2020
Simulation of ballistic phonon flights

In this project we study quasi-ballistic heat conduction in semiconductor nanowires. By probing phonons transport in nanowires of different length, shapes, and chemical compositions, we try to demonstrate non-diffusive thermal transport that takes place at nanoscale. Moreover, we measure the thermal properties of nanowires at different temperatures and show how the ballistic heat conduction becomes stronger as temperature is decreased to 4 K. In general, this project aims to uncover the length and temperature ranges in which ballistic heat conduction can enhance heat dissipation in microelectronic devices.

ballistic

The figure above summarizing our results showing ballistic heat conduction. (a) Thermal resistance measured on straight Si nanowires shows that the values deviate from linear dependence typical for diffusive transport, which indicates presence of ballistic thermal transport. (b) Thermal conductivity measured on straight nanowires is higher than that measured on serpentine nanowires, but this difference disappears above 200 K, which shows the range in which ballistic heat conduction occurs. (c) Heat focusing effect based on the ballistic thermal transport. Experimental results agree with Monte Carlo simulations

In progress

Related

Publications

A graphite thermal Tesla valve driven by hydrodynamic phonon transport

We demonstrate the rectification of heat conduction using micrometre-scale Tesla valve with the difference in thermal conductivity between opposite directions at 45 K.
Xin Huang, Roman Anufriev, Laurent Jalabert, Kenji Watanabe, Taniguchi Takashi, Yangyu Guo, Yuxiang Ni, Sebastian Volz, Masahiro Nomura
Nature 634, 1086 (2024).
Project Link

Quasi-ballistic thermal transport in silicon carbide nanowires

Investigation of the length and temperature scales at which SiC nanowires exhibits quasi-ballistic thermal conduction.
Roman Anufriev, Yunhui Wu, Sebastian Volz, Masahiro Nomura
Applied Physics Letters 124, 022202 (2024).
Project Link

Ballistic heat conduction in semiconductor nanowires

In this Perspective article, we review the experimental demonstrations of this phenomenon in nanowires of various materials and sizes and at different temperatures.
Roman Anufriev, Yunhui Wu, Masahiro Nomura
Journal of Applied Physics 130, 070903 (2021).
Project Link

Semiballistic thermal conduction in polycrystalline SiGe nanowires

We experimentally investigate ballistic thermal transport in SiGe polycrystalline nanowires by measuring the length dependence of thermal conductivity for different alloy compositions and temperatures.
Noboru Okamoto, Ryoto Yanagisawa, Roman Anufriev, Mahfuz Alam, Md., Sawano Kentarou, Masashi Kurosawa, Masahiro Nomura
Applied Physics Letters 115, 253101 (2019).
Project Link

Probing ballistic thermal conduction in segmented silicon nanowires

Here, we experimentally probed ballistic thermal transport at distances of 400–800 nm and temperatures of 4–250 K. Measuring thermal properties of straight and serpentine silicon nanowires, we found that at 4 K heat conduction is quasi-ballistic with stronger ballisticity at shorter length scales.
Roman Anufriev, Sergei Gluchko, Sebastian Volz, Masahiro Nomura
Nanoscale 11, 13407 (2019).
Project Link

Quasi-ballistic heat conduction due to Lévy phonon flights in silicon nanowires

Here, we experimentally demonstrate quasi-ballistic heat conduction in silicon nanowires (NWs). We show that the ballisticity is the strongest in short NWs at low temperatures but weakens as the NW length or temperature is increased.
Roman Anufriev, Sergei Gluchko, Sebastian Volz, Masahiro Nomura
ACS Nano 12, 11928 (2018).
Project Project Link

Heat guiding and focusing using ballistic phonon transport in phononic nanostructures

Here, we show a method to control the directionality of ballistic phonon transport using silicon membranes with arrays of holes.
Roman Anufriev, Aymeric Ramiere, Jeremie Maire, Masahiro Nomura
Nature Communications 8, 15505 (2017).
Project Project Link

Ballistic thermal transport in silicon nanowires

We have experimentally investigated the impact of dimensions and temperature on the thermal conductivity of silicon nanowires fabricated using a top-down approach.
Jeremie Maire, Roman Anufriev, Masahiro Nomura
Scientific Reports 7, 41794 (2017).
Project Link