Efficient calculation of carrier scattering rates from first principles

Abstract

The electronic transport behaviour of materials determines their suitability for technological applications. We develop a computationally efficient method for calculating carrier scattering rates of solid-state semiconductors and insulators from first principles inputs. The present method extends existing polar and non-polar electron-phonon coupling, ionized impurity, and piezoelectric scattering mechanisms formulated for isotropic band structures to support highly anisotropic materials. We test the formalism by calculating the electronic transport properties of 23 semiconductors, including the large 48 atom CH3NH3PbI3 hybrid perovskite, and comparing the results against experimental measurements and more detailed scattering simulations. The Spearman rank coefficient of mobility against experiment (rs = 0.93) improves significantly on results obtained using a constant relaxation time approximation (rs = 0.52). We find our approach offers similar accuracy to state-of-the art methods at approximately 1/500th the computational cost, thus enabling its use in high-throughput computational workflows for the accurate screening of carrier mobilities, lifetimes, and thermoelectric power.

Ca4Sb2O and Ca4Bi2O: two promising mixed-anion thermoelectrics

“…The electronic transport properties were calculated using the AMSET software package. 48 The code uses the momentum relaxation time approximation (MRTA) 49 to calculate the scattering rates and carrier mobilities, and has demonstrated excellent agreement both to experimental measurements of the electron mobilities and Seebeck coefficients of several semiconductors and to highly-accurate theoretical calculations using the electron-phonon Wannier approach. 48,50–52 Unlike the widely-used BoltzTraP approach, 53 this method does not assume a constant relaxation time and instead estimates one by considering a range of scattering processes.…”

“…The mode dependent scattering rates for each process are obtained within the Born approximation using common materials parameters, with differential scattering rates from state | n k 〉 to state | m k + q 〉 calculated using Fermi's golden rule: 48 where ε n k represents the energy of the state | n k 〉, and g nm ( k , q ) is the matrix element for scattering from state | n k 〉 into state | m k + q 〉.…”

Electron, phonon and thermoelectric properties of Cu7PS6 crystal calculated at DFT level

“…2 a). In the inset, the effective mass m * , obtained on the basis of the relation ( 3 ), where the values μ and τ were calculated using AMSET code 30 at the temperature 300 K ( https://hackingmaterials.lbl.gov/amset/ ). …”

“…Afterward, the power factor PF and the figure of merit ZT , as the main thermoelectric values, may be calculated using the BoltzTrap2 code. In the present study, the thermoelectric properties of Cu 7 PS 6 were calculated using the new AMSET code 30 , which uses also the BoltzTrap2 one.…”

“…The thermoelectric properties of Cu 7 PS 6 were calculated using the recently published AMSET code 30 developed on the basis of VASP and BoltzTraP2 16 , 17 . The BoltzTraP2 code is based on the semi-classical Boltzmann transport theory 42 with the density of electron states (DOS) only as input.…”