Interplay of point defects, biaxial strain, and thermal conductivity in homoepitaxial SrTiO3 thin films

Wiedigen, S.; Kramer, Thilo; Feuchter, M; Knorr, Inga; Nee, N.; Hoffmann, J.; Kamlah, Marc; Volkert, Cynthia A.; Jooß, Ch.

doi:10.1063/1.3682300

Cited by 22 publications

(21 citation statements)

References 20 publications

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“…Growth temperature has been reported to affect both film lattice constant and thermal conductivity in homoepitaxial SrTiO 3 films deposited by sputtering. 48 For a comparable range of temperatures, our results show a similar though lesser effect ($30%) without the clear difference in out-of-plane lattice constants from XRD. The stoichiometric film deposited in distilled ozone ($80% O 3 ) at 650 C shows the highest longitudinal thermal conductivity, 11.5 W/mÁK at room temperature.…”

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confidence: 57%

Tuning thermal conductivity in homoepitaxial SrTiO3 films via defects

Brooks

Wilson

Schäfer³

et al. 2015

Applied Physics Letters

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We demonstrate the ability to tune the thermal conductivity of homoepitaxial SrTiO3 films deposited by reactive molecular-beam epitaxy by varying growth temperature, oxidation environment, and cation stoichiometry. Both point defects and planar defects decrease the longitudinal thermal conductivity (k33), with the greatest decrease in films of the same composition observed for films containing planar defects oriented perpendicular to the direction of heat flow. The longitudinal thermal conductivity can be modified by as much as 80%—from 11.5 W m−1K−1 for stoichiometric homoepitaxial SrTiO3 to 2 W m−1K−1 for strontium-rich homoepitaxial Sr1+δTiOx films—by incorporating (SrO)2 Ruddlesden-Popper planar defects.

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supporting

confidence: 57%

Tuning thermal conductivity in homoepitaxial SrTiO3 films via defects

Brooks

Wilson

Schäfer³

et al. 2015

Applied Physics Letters

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“…30, κ L (800 K)=0.553 W m −1 K −1 is estimated using the reciprocal relation of κ L to T . Generally, under biaxial strain, lattice thermal conductivity is lower than that without strain because of the enhancement of phonon scattering by strain-induced defects47, which is beneficial to TE performance. To study the contribution to zT from electrical transport, lattice thermal conductivity here was assumed to be independent of biaxial strain.…”

Section: Methodsmentioning

confidence: 99%

Designing high-performance layered thermoelectric materials through orbital engineering

et al. 2016

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Thermoelectric technology, which possesses potential application in recycling industrial waste heat as energy, calls for novel high-performance materials. The systematic exploration of novel thermoelectric materials with excellent electronic transport properties is severely hindered by limited insight into the underlying bonding orbitals of atomic structures. Here we propose a simple yet successful strategy to discover and design high-performance layered thermoelectric materials through minimizing the crystal field splitting energy of orbitals to realize high orbital degeneracy. The approach naturally leads to design maps for optimizing the thermoelectric power factor through forming solid solutions and biaxial strain. Using this approach, we predict a series of potential thermoelectric candidates from layered CaAl2Si2-type Zintl compounds. Several of them contain nontoxic, low-cost and earth-abundant elements. Moreover, the approach can be extended to several other non-cubic materials, thereby substantially accelerating the screening and design of new thermoelectric materials.

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“…The thermal properties of undoped STO were studied using a variety of growth methods to verify the ability of each technique in producing high quality STO films. 121,122 Thin…”

Section: A Titanatesmentioning

confidence: 99%

Thermoelectric and thermal transport properties of complex oxide thin films, heterostructures and superlattices

Ravichandran

2016

J. Mater. Res.

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Over the years, the search for high performance thermoelectric materials has been dictated by the "phonon glass and electron crystal (PGEC)" paradigm, which suggests that low band gap semiconductors with high atomic number elements and high carrier mobility are the ideal materials to achieve high thermoelectric figure of merit. Complex oxides provide alternative mechanisms such as large density of states and strong electron correlation for high thermoelectric efficiency, albeit having low carrier mobility. Due to vast structural and chemical flexibility, they provide a fertile playground to design high efficiency thermoelectric materials. Further, developments in oxide thin film growth methods have enabled synthesis of high quality, atomically precise low dimensional structures such as heterostructures and superlattices. These materials and structures act as excellent model systems to explore nanoscale thermal and thermoelectric transport, which will not only expand the frontier of our knowledge, but also continue to enable cutting edge applications.

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Interplay of point defects, biaxial strain, and thermal conductivity in homoepitaxial SrTiO3 thin films

Cited by 22 publications

References 20 publications

Tuning thermal conductivity in homoepitaxial SrTiO3 films via defects

Tuning thermal conductivity in homoepitaxial SrTiO3 films via defects

Designing high-performance layered thermoelectric materials through orbital engineering

Thermoelectric and thermal transport properties of complex oxide thin films, heterostructures and superlattices

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