PSI - Issue 23

Available online at www.sciencedirect.com Available online at www.sciencedirect.com Available online at www.sciencedirect.com

ScienceDirect

Procedia Structural Integrity 23 (2019) 334–341 Structural Integrity Procedia 00 (2019) 000–000 Structural Integrity Procedia 00 (2019) 000–000

www.elsevier.com / locate / procedia www.elsevier.com / locate / procedia

© 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the ICMSMF organizers Abstract In the post-graphene era, there has been a significant upsurge of interest on the mechanical and thermal properties of two dimen sional graphene-like honeycomb structures made of other group-IV elements. This article deals with application of first principle based density functional theory to investigate the lattice dynamics of the members of this extended graphene family. We explore the changes observed in the lattice thermal conductivity, adopting physical models for estimating phonon lifetimes. We use the Asen-Palmer modified version of Debye-Callaway theory to calculate the lattice thermal conductivity of graphene, as well as of low and double buckled silicene, germanene, and stanene. This allows us to establish a connection between the parameters such as group velocity, Gru¨neisen parameter, and Debye temperature of the acoustic phonon modes and the lattice thermal conductivity. Our calculations show that the presence of buckling reduces the group velocity and the Debye temperature of the sheets down the group, and hence, reduces their lattice thermal conductivity. However, there is no linear dependence between the buckling height and the observed lowering. An increase in buckling height in sheets with di ff erent geometries of the same atomic species, beyond a certain limit, does not lead to change in the group velocity and the Debye temperature of the sheets. c 2019 The Authors. Published by Elsevier B.V. his is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) eer-review under responsibility of the scientific committee of the IC MSMF organizers. Keywords: Density functional theory; vibrational dynamics; thermal conductivity; graphene; silicene; germanene; stanene. Abstract In the post-graphene era, there has been a significant upsurge of interest on the mechanical and thermal properties of two dimen sional graphene-like honeycomb structures made of other group-IV elements. This article deals with application of first principle based density functional theory to investigate the lattice dynamics of the me bers of this extended graphene fa ily. e explore the changes observed in the lattice thermal conductivity, adopting physical models for estimating phonon lifetimes. We use the Asen-Palmer modified version of Debye-Callaway theory to calculate the lattice thermal conductivity of graphene, as well as of low and double buckled silicene, germanene, and stanene. This allows us to establish a connection between the parameters such as group velocity, Gru¨neisen parameter, and Debye temperature of the acoustic phonon modes and the lattice thermal conductivity. Our calculations show that the presence of buckling reduces the group velocity and the Debye temperature of the sheets down the group, and hence, reduces their lattice thermal conductivity. However, there is no linear dependence between the buckling height and the observed lowering. An increase in buckling height in sheets with di ff erent geometries of the same atomic species, beyond a certain limit, does not lead to change in the group velocity and the Debye temperature of the sheets. c 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of the scientific committee of the IC MSMF organizers. Keywords: Density functional theory; vibrational dynamics; thermal conductivity; graphene; silicene; germanene; stanene. 9th International Conference on Materials Structure and Micromechanics of Fracture Phonons and lattice thermal conductivities of graphene family Gour P. Das a, ∗ , Parul R. Raghuvanshi b , Amrita Bhattacharya b a Dept. of Metallurgical and Materials Engineering, Indian Institute of Technology Kharagpur, Kharagpur - 721302, India b Dept. of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai- 400076, India 9th International Conference on Materials Structure and Micromechanics of Fracture Phonons and lattice thermal conductivities of graphene family Gour P. Das a, ∗ , Parul R. Raghuvanshi b , Amrita Bhattacharya b a Dept. of Metallurgical and Materials Engineering, Indian Institute of Technology Kharagpur, Kharagpur - 721302, India b Dept. of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai- 400076, India

1. Introduction 1. Introduction

Advent of graphene discovered by Geim and Novoselov (2007) and subsequently an avalanche of graphene inspired 2D materials evoked a paradigm shift in our conception of the world of nanomaterials. This is because of our capability to extract single atom thick layers of materials whose bulk counterparts have been well known for ages. Also, it resulted in stacked multilayers of di ff erent 2D materials with weak van der Waals inter-plane bonding (Geim and Grigorieva, 2015) , as well as novel in-plane heterojunctions of two or more 2D materials (Pant et al., 2016). All these have opened up the possibility of a large variety of structural, electronic, magnetic, optical, thermal and other properties of the 2D and quasi-2D material families as investigated in Bhattacharya et al. (2010) and Bhattacharya et al. (2011). It is well known that the Gr-IV analogues of graphene, viz. silicene, germanene, stanene manifest a Advent of graphene discovered by Geim and Novoselov (2007) and subsequently an avalanche of graphene inspired 2D materials evoked a paradigm shift in our conception of the world of nanomaterials. This is because of our capability to extract single atom thick layers of materials whose bulk counterparts have been well known for ages. Also, it resulted in stacked multilayers of di ff erent 2D materials with weak van der Waals inter-plane bonding (Geim and Grigorieva, 2015) , as well as novel in-plane heterojunctions of two or more 2D materials (Pant et al., 2016). All these have opened up the possibility of a large variety of structural, electronic, magnetic, optical, thermal and other properties of the 2D and quasi-2D material families as investigated in Bhattacharya et al. (2010) and Bhattacharya et al. (2011). It is well known that the Gr-IV analogues of graphene, viz. silicene, germanene, stanene manifest a

2452-3216 © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the ICMSMF organizers 10.1016/j.prostr.2020.01.109 ∗ Corresponding author. E-mail address: gpdas@metal.iitkgp.ac.in 2210-7843 c 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of the scientific committee of the IC MSMF organizers. ∗ Corresponding author. E-mail address: gpdas@metal.iitkgp.ac.in 2210-7843 c 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of the scientific committee of the IC MSMF organizers.