2020/10/12 by John W. Villanova, Salvador Barraza-Lopez, Salvador Barraza‐Lopez · 27 citations
Chemistry · Engineering · Materials Science · Physics and Astronomy · #2D Materials and Applications #Advanced Thermoelectric Materials and Devices #Chalcogenide Semiconductor Thin Films #Chemical physics #Chemistry #Condensed matter physics #Crystallography #Materials science #Monolayer #Nanotechnology #Physics #Thermodynamics #Thermoelectric effect #Transition (genetics) #cond-mat.mes-hall #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.103.035421
published in Physical review. B./Physical review. B 103(3) (American Physical Society) · Originally submitted on May 12, 2020
arxiv created 2020/10/12 · openalex created_date 2020/10/15 · openalex publication_date 2021/01/21 · arxiv updated 2021/01/22 · openalex updated_date 2026/08/05
The thermoelectric figure of merit ZT comprises electronic and vibrational contributions that drastically change across phase transitions, and the most common theoretical ab initio approach to thermoelectricity fails to describe the evolution of ZT across finite-temperature structural transitions in its entirety. Furthermore, while the thermoelectric behavior of bulk SnSe has been extensively studied, SnSe monolayers have been experimentally realized only recently, and the existent prediction of thermoelectricity on this two-dimensional material is unreliable because it misses its structural transition altogether. SnSe monolayers (and similar GeS, GeSe, GeTe, SnS, and SnTe monolayers) experience a temperature-induced two-dimensional Pnm21\ensuremath→P4/nmm structural transition precipitated by the softening of vibrational modes, and we describe their thermoelectric properties across the phase transition, using molecular dynamics data to inform both electronic and vibrational coefficients directly and within the same footing. Similar to recent experimental observations pointing to an overestimated ZT past the transition temperature in bulk SnSe, we find a smaller ZT on SnSe monolayers when compared to its value predicted by the standard paradigm, due to the dramatic changes in the electrical conductivity and lattice thermal conductivity as the structural transition ensues. The process described here lends a strong focus to both the vibrational and electronic evolutions throughout the structural transition, and it applies to thermoelectric materials undergoing thermally driven solid-to-solid structural phase transitions in one, two, and three dimensions.