Title: Effects of Aperiodicity and Roughness on Coherent Heat Conduction in Superlattices

Abstract

Coherent phonon heat conduction has recently been confirmed experimentally in superlattice structures. Such traveling coherent phonon waves in superlattices lead to a linear increase in thermal conductivity as the number of periods increases. For applications such as thermal insulation or thermoelectrics, minimization of the phonon coherent effect is desirable. In this paper, we use molecular dynamics simulations to study how to control coherent heat conduction in superlattices (SLs). It is found that either aperiodic SLs or SLs with rough interfaces can significantly disrupt coherent heat conduction when the interface densities are high. For sample thickness less than 125 nm, aperiodic SLs with perfect interfaces are found to have the lowest thermal conductivity. We use the atomic Green’s function method to examine the phonon dynamics. The impact of either aperiodicity or interface roughness is attributed to reduced transmittance. Such impact diminishes as the interface density reduces.

Authors:

Qiu, Bo ^[1]; Chen, Gang ^[1]; Tian, Zhiting ^[2]

---

+ Show Author Affiliations

1. Massachusetts Inst. of Technology, Cambridge, MA (United States). Dept. of Mechanical Engineering
2. Virginia Tech, Blacksburg, VA (United States). Dept. of Mechanical Engineering

Publication Date:

Tue Dec 15 00:00:00 EST 2015

Research Org.:

Energy Frontier Research Centers (EFRC) (United States). Solid-State Solar-Thermal Energy Conversion Center (S3TEC)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1370984

Grant/Contract Number:  

SC0001299; FG02-09ER46577

Resource Type:

Accepted Manuscript

Journal Name:

Nanoscale and Microscale Thermophysical Engineering

Additional Journal Information:

Journal Volume: 19; Journal Issue: 4; Related Information: S3TEC partners with Massachusetts Institute of Technology (lead); Boston College; Oak Ridge National Laboratory; Rensselaer Polytechnic Institute; Journal ID: ISSN 1556-7265

Publisher:

Taylor & Francis

Country of Publication:

United States

Language:

English

Subject:

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; solar (photovoltaic); solar (thermal); solid state lighting; phonons; thermal conductivity; thermoelectric; defects; mechanical behavior; charge transport; spin dynamics; materials and chemistry by design; optics; synthesis (novel materials); synthesis (self-assembly); synthesis (scalable processing); superlattice; molecular dynamics; atomic green's function