Inverse Design of Ultralow Lattice Thermal Conductivity Materials via Materials Database Screening of Lone Pair Cation Coordination Environment

The
presence of lone pair (LP) electrons is strongly associated
with the disruption of lattice heat transport, which is a critical
component of strategies to achieve efficient thermoelectric energy
conversion. By exploiting an empirical relationship between lattice
thermal conductivity, κL, and the bond angles of
pnictogen group LP cation coordination environments, we develop an
inverse design strategy based on a materials database screening to
identify chalcogenide materials with ultralow κL for
thermoelectrics. Screening the ∼635 000 real and hypothetical
inorganic crystals of the Open Quantum Materials Database based on
the constituent elements, nominal electron counting, LP cation coordination
environment, and synthesizability, we identify 189 compounds expected
to exhibit ultralow κL. As a validation, we explicitly
compute the lattice dynamical properties of two of the compounds (Cu2AgBiPbS4 and MnTl2As2S5) using first-principles calculations and successfully find
both achieve ultralow κL values at room temperature
of ∼0.3–0.4 W/(m·K) corresponding to the amorphous
limit. Our data-driven approach provides promising candidates for
thermoelectric materials and opens new avenues for the design of phononic
properties of materials.