Lattice thermal conduction in suspended molybdenum disulfide monolayers with defects

Title

Lattice thermal conduction in suspended molybdenum disulfide monolayers with defects

Creator

Patil S.B.; Sankeshwar N.S.; Mulimani B.G.

Description

In this study, we investigated the effect of lattice defects comprising vacancies and boundaries on the lattice thermal conductivity (LTC), ? p , of suspended molybdenum disulfide monolayers (MLs) over a wide temperature range (1 < T < 500 K). Using the phonon Boltzmann formalism, the acoustic phonons were considered to be scattered by the sample and grain boundaries, isotopic impurities, vacancies, and other phonons via Umklapp and normal (N-) processes. ? p was evaluated using a modified Callaway model by considering the in-plane longitudinal acoustic and transverse acoustic phonons, and out-of-plane flexural acoustic phonon modes. We demonstrated the need to include the often neglected non-resistive N-processes when evaluating the LTC. Numerical calculations of the temperature dependence of the LTC for crystalline and polycrystalline MoS 2 MLs showed the dominance of sample-dependent scattering mechanisms at low temperatures (T < 100 K) and of phonon-phonon scattering at higher temperatures, where the N-processes played an important role. The effects of vacancies and boundaries were to alter the behavior and suppress the magnitude of the LTC. The suppression due to vacancies was greater in crystalline MLs with specular surfaces and in polycrystalline MLs with larger grain sizes. The calculations compared well with recent thermal conductivity data obtained for polycrystalline samples. The need for further investigations is suggested. 2018 Elsevier Ltd

Source

Journal of Physics and Chemistry of Solids, Vol-129, pp. 31-40.

Date

2019-01-01

Publisher

Elsevier Ltd

Subject

Grain boundary scattering; Lattice thermal conductivity; MoS ₂ monolayer ; N-process; Vacancy scattering

Coverage

Patil S.B., Department of Physics, Karnatak University, Dharwad, 580003, Karnataka, India; Sankeshwar N.S., Department of Physics, Karnatak University, Dharwad, 580003, Karnataka, India, Department of Physics, Christ University, Bangalore, 560029, Karnataka, India; Mulimani B.G., Department of Physics, Karnatak University, Dharwad, 580003, Karnataka, India

Rights

Restricted Access

Relation

ISSN: 223697; CODEN: JPCSA

Format

Online

Language

English

Type

Article

Identifier

https://doi.org/10.1016/j.jpcs.2018.12.032

https://www.scopus.com/inward/record.uri?eid=2-s2.0-85059463464&doi=10.1016%2fj.jpcs.2018.12.032&partnerID=40&md5=2f6169c84150d52ea6831725538a78e1