5:00 PM - QN05.06.35
Investigation on Thermal Conductivity of BAs Monolayer—A First-Principles Study
Zhongyong Wang1,Lei Liu1,Rui Dai1,Qiong Nian1,Houlong Zhuang1,Robert Wang1
Arizona State University1
Cubic boron arsenide (BAs) bulk crystal has been identified to have an ultrahigh thermal conductivity (~1300Wm-1K-1) both theoretically1 and experimentally2-4. On the other hand, two-dimensional (2D) stable monolayers of BAs have also been reported to have promising electronic, transport, optical and thermoelectric properties5. However, the thermal conductivity of BAs monolayer has not yet been investigated. Does thermal transport in BAs monolayers parallel that of cubic BAs bulk crystals? We present our first-principles study on the thermal conductivity of BAs monolayer.
The vibrational spectra of BAs monolayers have been calculated and are quite different from that of cubic BAs bulk crystals5. Two transversal acoustic and optical branches, which correspond to out-of-plane atomic vibrations in BAs monolayers, carry lower energy due to the fact that atoms can more easily vibrate perpendicular to the plane. The so-called “acoustic bunching” behavior in cubic BAs is also not seen in the vibrational spectra of BAs monolayer due to the presence of these out-of-plane branches. Nonetheless, the giant phononic band gap between the acoustic branches and two in-plane optical branches still exists in the vibrational spectra of BAs monolayers. At this point, qualitative analysis of thermal conductivity based on the vibration spectra is inconclusive. More rigorous computational calculations need to be performed to derive the lattice thermal conductivity of BAs monolayers.
For our computations, we employ density-functional perturbation theory to generate second-order (harmonic) and third-order (anharmonic) interatomic force constants (IFC) for BAs monolayer using the VASP package. The harmonic IFC allows us to derive the vibrational properties, while the anharmonic IFC allows us to determine the three-phonon scattering rates using Fermi’s golden rule. With the only inputs of harmonic and anharmonic IFC, we can derive the lattice thermal conductivity by solving the exact phonon Boltzmann Transport Equation using the ShengBTE package6.
1. L. Lindsay, D. A. Broido and T. L. Reinecke, Phys Rev Lett, 2013, 111, 025901.
2. F. Tian, B. Song, X. Chen, N. K. Ravichandran, Y. C. Lv, K. Chen, S. Sullivan, J. Kim, Y. Y. Zhou, T. H. Liu, M. Goni, Z. W. Ding, J. Y. Sun, G. A. G. U. Gamage, H. R. Sun, H. Ziyaee, S. Y. Huyan, L. Z. Deng, J. S. Zhou, A. J. Schmidt, S. Chen, C. W. Chu, P. S. E. Y. Huang, D. Broido, L. Shi, G. Chen and Z. F. Ren, Science, 2018, 361, 582.
3. J. S. Kang, M. Li, H. A. Wu, H. Nguyen and Y. J. Hu, Science, 2018, 361, 575-578.
4. S. Li, Q. Y. Zheng, Y. C. Lv, X. Y. Liu, X. Q. Wang, P. S. E. Y. Huang, D. G. Cahill and B. Lv, Science, 2018, 361, 579-581.
5. K. Manoharan and V. Subramanian, Acs Omega, 2018, 3, 9533-9543.
6. W. Li, J. Carrete, N. A. Katcho and N. Mingo, Comput Phys Commun, 2014, 185, 1747-1758.