Thermoelectric Properties from Ab Initio Calculations Gustavo Javier-Rico1, David M. Guzman2, and Alejandro H. Strachan2 1Department of Physics, California State University of Los Angeles 2School of Materials Engineering and Birck Nanotechnology Center Purdue University, West Lafayette IN

Motivation Challenge Results: Thermoelectric Transport Properties The implemented DFT tool

. • Simulations are becoming increasingly important. • LanTraP needs the output band structure files DFT MatProp produces. = 𝐿𝐿⊥ 𝑑𝑑−1 • Simulations are just as important as experiment for the • DFT MatProp output files are not in the format LanTraP requires. + 𝑑𝑑−1 𝑀𝑀 𝜖𝜖 2𝜋𝜋 ∫𝐵𝐵𝐵𝐵 ∑𝑛𝑛 Θ 𝜖𝜖 − 𝜖𝜖𝑘𝑘⊥ 𝑑𝑑𝑘𝑘⊥ search of energy efficient devices. • The density of modes is the number of channels of conduction. • Although these two tools are intimately connected, they’re presently incompatible. = ( ) d + = 2𝑞𝑞 • For the𝐼𝐼 LDL equation� 𝑇𝑇of current,𝜖𝜖 𝑀𝑀 𝜖𝜖 density𝑓𝑓1 − of𝑓𝑓 modes2 ϵ appears as a fundamentalℎ quantity. [4] Results Experiment Simulation Device

What is DFT Materials ≠ Properties Simulator? Methods: Generate full band dispersion Output file suitable for LanTraP

DFT Materials Properties Simulator is a user friendly nanoHUB DFT MatProp is used to calculate the electronic band dispersion simulation tool that calculates electronic band structures of of Silicon: arbitrary materials. [1] Conclusion

There is an invaluable connection between the two nanoHUB tools DFT Materials Properties and LanTraP. Such connection is often overlooked because of the complex process of generating the required inputs. This study was a first step to bridge these tools. Full-band electron dispersions have been implemented; however, support for phonon dispersions will be implemented in a follow up release of the tool. The connection between DFTMatProp and LanTrap provides the necessary tools to explore arbitrary thermoelectric materials form first principles calculations. References DFT MatProp uses Density Functional Theory as its theoretical Density of Modes Electrical Conductivity Seebeck Coefficient Thermal Conductivity [1] Kamran, Usama,. Guzman, M. David,. and Strachan, Alejandro(2015), “DFT Material machine, and Quantum Espresso software. Properties Simulator,” https://nanohub.org/resources/dftmatprop.(DOI: 10.4231/D3DF5K44C).

𝑀𝑀 𝜖𝜖 𝜎𝜎 𝑠𝑠 𝜅𝜅 [2] Conrad, Kyle,. Maassen, Jesse., and Lundstrom, Mark(2014)., “LanTraP,” With all the TE coefficients in place, the electronic ZT https://nanohub.org/resources/lantrap. (DOI: 10.4231/D3NP1WJ64). What is LanTraP? figure of merit can be calculated. The ZT figure of merit [3] Jeong, Changwook., Kim, Reasong., Luisier, Mathieu., Datta, Supriyo., and LanTraP is a nanoHUB online tool that calculates thermoelectric Structure the output file to be LanTraP friendly characterizes the performance of a device. Lundstrom, Mark., “On Landauer Versus Boltzmann and Full Band Versus Effective Mass Evaluation of Thermoelectric Transport Coefficients,” Journal of Applied Physics, 107, properties of materials. [2] The Landauer-Datta-Lundstrom model for 023707, 2010. thermoelectric transport suggests that thermoelectric calculations [4] Kruglyak, Yuriy., “Landauer-Datta-Lundstrom Generalized Transport Model for can be made from full band dispersion data. [3] Nanoelectronics,” Review Article , Volume 2014, Article ID 725420

= A band structure file Acknowledgements must be uploaded to =𝜎𝜎 𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸 𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶 LanTraP = =𝑆𝑆 𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆 𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶 I would like to thank the nanoHUB technical support Team, SURF and NCN, and the physics department at 𝜅𝜅 𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸 𝑇𝑇𝑇𝑇𝑇𝑇�𝑇𝑇𝑇𝑇𝑇𝑇 𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶 California State University of Los Angeles.

This work is funded by the National Science Foundation, Network for Computational Nanotechnology Cyberplatform, Award EEC-1227110. Any opinions, findings, conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.