Establishment Of First-principles Repository And High-throughput Screening Of Thermoelectric Materials

Accelerating the process of materials research and development has become a common pursuit in all countries around the world.How to quickly obtain new materials based on low cost and highly reliable prediction methods to guide experiments is an important issue.Traditional materials research and development mainly rely on trial and error,which consumes considerable time and resources.In 2011,the White House proposed the “Materials Genome Initiative”(MGI).The project consists of three parts:high-throughput(HTP)calculations,experimental methods,and digital databases.Among them,the material database is a crucial part.After the proposal of the MGI,several high-throughput digital material databases based on first-principles calculations have emerged,these databases have greatly promoted the development of the materials field.In this work,we have established our own electronic material database,the Materials informatics platform with three dimensional structures(MIP-3d).Our initial purpose was to apply big data technology to functional materials(such as thermoelectric materials)of interest.To date,MIP-3d has recorded over 31,000 electronic structures,12,000 equations of state and sound velocities calculated by this work.About 4,400 transport data calculated by home-made packages such as Trans Opt were integrated into MIP-3d.For entries with finite band gaps,the band degeneracy for the band-edge states has been analyzed.Band degeneracy serves as a convenient search criterion for good thermoelectric materials.The calculations of the band degeneracies and electrical transport properties make MIP-3d a database specifically designed for thermoelectric applications.The calculation results of this work are open to all scientific researchers.In short,the calculation results and visual display of MIP-3d can provide some help to future materials researchers,and also provide a data basis for machine learning and high-throughput screening of thermoelectric materials.On the other hand,the main problem in the application of thermoelectric materials is that the conversion efficiency is not high.In order to obtain materials with higher thermoelectric conversion efficiency,it is required to have higher electrical conductivity and Seebeck coefficient,as well as lower thermal conductivity.However,these thermoelectric parameters are coupled with each other,making it difficult to optimize one of these parameters individually.MIP-3d has recorded the electrical transport properties of more than 4,400 materials,so we chose to directly use highthroughput screening to find new thermoelectric materials.Because materials with low sound velocity are likely to have lower thermal conductivity,which is conducive to obtaining better thermoelectric properties,finally,based on the calculation results of MIP-3d,we conducted high-throughput screening under the conditions of the power factor and sound velocity of the material.And finally we predicted 85 n-type compounds and 90 p-type compounds,there may be new types of thermoelectric materials among them.