Work

The use of strain and grain boundaries to tailor phonon transport properties: A first-principles study of 2H-phase CuAlO2. II

Year: 2020

Type: article

Abstract: Transparent oxide materials, such as CuAlO2, a p-type transparent conducting oxide (TCO), have recently been studied for high temperature thermoelectric power generators and coolers for waste heat. TCO materials are generally low cost and non-toxic. The potential to engineer them through strain and nano-structuring are two promising avenues toward continuously tuning the electronic and thermal properties to achieve high zT values and low $cost/kW h devices. In this work, the strain-dependent lattice thermal conductivity of 2H CuAlO2 is computed by solving the phonon Boltzmann transport equation with interatomic force constants extracted from first-principles calculations. While the average bulk thermal conductivity is around 32 W/(m K) at room temperature, it drops to between 5 and 15 W/(m K) for typical experimental grain sizes from 3 nm to 30 nm. We find that strain can offer both an increase as well as a decrease in the thermal conductivity as expected; however, the overall inclusion of small grain sizes dictates the potential for low thermal conductivity in this material.

Source: Journal of Applied Physics

DOI: 10.1063/1.5142485

Authors: Evan Witkoske, Zhen Tong, Yining Feng, Xiulin Ruan, Mark Lundstrom, Na Lu

Institution: Purdue University West Lafayette

Language: English

Topic: Thermal properties of materials

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: green

Funders: National Science Foundation, Division of Civil, Mechanical and Manufacturing Innovation

Award: CAREER: Investigating Process-Structure-Property Correlations of Nitrides and Oxides for High Temperature Thermoelectric Applications