The effective mass is a convenient descriptor of the electronic band structure used to characterize the density of states and electron transport based on a free electron model.While effective mass is an excellent firs...The effective mass is a convenient descriptor of the electronic band structure used to characterize the density of states and electron transport based on a free electron model.While effective mass is an excellent first-order descriptor in real systems,the exact value can have several definitions,each of which describe a different aspect of electron transport.Here we use Boltzmann transport calculations applied to ab initio band structures to extract a density-of-states effective mass from the Seebeck Coefficient and an inertial mass from the electrical conductivity to characterize the band structure irrespective of the exact scattering mechanism.We identify a Fermi Surface Complexity Factor:N_(v)^(*)K^(*) from the ratio of these two masses,which in simple cases depends on the number of Fermi surface pockets eN_(v)^(*) T and their anisotropy K^(*),both of which are beneficial to high thermoelectric performance as exemplified by the high values found in PbTe.The Fermi Surface Complexity factor can be used in high-throughput search of promising thermoelectric materials.展开更多
基金intellectually led by the Materials Project which is supported by the Department of Energy Basic Energy Sciences program under Grant No.EDCBEE,DOE Contract DE-AC02-05CH11231supported by the Office of Science of the U.S.Department of Energysupported by the F.R.S.-FNRS project HTBaSE(contract no.PDR-T.1071.15)。
文摘The effective mass is a convenient descriptor of the electronic band structure used to characterize the density of states and electron transport based on a free electron model.While effective mass is an excellent first-order descriptor in real systems,the exact value can have several definitions,each of which describe a different aspect of electron transport.Here we use Boltzmann transport calculations applied to ab initio band structures to extract a density-of-states effective mass from the Seebeck Coefficient and an inertial mass from the electrical conductivity to characterize the band structure irrespective of the exact scattering mechanism.We identify a Fermi Surface Complexity Factor:N_(v)^(*)K^(*) from the ratio of these two masses,which in simple cases depends on the number of Fermi surface pockets eN_(v)^(*) T and their anisotropy K^(*),both of which are beneficial to high thermoelectric performance as exemplified by the high values found in PbTe.The Fermi Surface Complexity factor can be used in high-throughput search of promising thermoelectric materials.
