Please use this identifier to cite or link to this item: http://dr.iiserpune.ac.in:8080/xmlui/handle/123456789/7063
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dc.contributor.authorSAURABH, KUMARen_US
dc.contributor.authorKUMAR, ANKITen_US
dc.contributor.authorGHOSH, PRASENJITen_US
dc.contributor.authorSINGH, SURJEETen_US
dc.date.accessioned2022-06-13T04:47:32Z
dc.date.available2022-06-13T04:47:32Z
dc.date.issued2022-06en_US
dc.identifier.citationPhysical Review Materials, 6(6), 065401.en_US
dc.identifier.issn2475-9953en_US
dc.identifier.urihttps://doi.org/10.1103/PhysRevMaterials.6.065401en_US
dc.identifier.urihttp://dr.iiserpune.ac.in:8080/xmlui/handle/123456789/7063
dc.description.abstractThe orthorhombic TiNiSi structure-type compounds show interesting electronic structures comprising in most cases a pseudogap in the density of states and several small electron and hole pockets at the Fermi energy. These features are promising and can be exploited to test their potential as thermoelectric materials for waste heat conversion. Here, we investigate the effect of electron doping in the semimetallic member ZrNiSi of this family. We show that by doping with Sb for Si in ZrNiSi, S and σ can both be increased simultaneously for initial Sb doping defying the oppositely directed trend commonly observed in most materials. In the doped samples, σ at 300K increases from 1000Scm−1 to as high as 2500Scm−1; at the same time, the peak value of S, which is −20μVK−1 in ZrNiSi, increases by more than a factor of two. The simultaneous enhancement of σ and S has been explained using the first-principles density functional theory based band structure calculations. The as-cast (i.e., unannealed) ZrNiSi1−xSbx samples show phase segregation due to a spinodal-type decomposition with two coexisting TiNiSi structure-type phases with different Sb/Si ratios. The thermal conductivity (κ) in the doped samples drops significantly from 12Wm−1K−1 (x=0) to nearly 2Wm−1K−1 (x=0.2) at 300 K. As a result, the peak thermoelectric figure of merit (zT) increases from 0.005 (x=0) to 0.023 (x=0.2). Further enhancement in zT is obtained by codoping of Hf (Zr site) and Sb (Si site), which improves the phase stability and chemical homogeneity while keeping the thermal conductivity still very low due to Zr-Hf point mass fluctuation, resulting in a peak zT value of 0.055, i.e., almost an order of magnitude higher value than for the pristine ZrNiSi. We show that the thermoelectric properties of TiNiSi structure-type semimetals can be enhanced by aliovalent doping. This principle can be employed on other members of the TiNiSi to improve the zT in this family of compounds further.en_US
dc.language.isoenen_US
dc.publisherAmerican Physical Societyen_US
dc.subjectPhysicsen_US
dc.subject2022-JUN-WEEK2en_US
dc.subjectTOC-JUN-2022en_US
dc.subject2022en_US
dc.titleEnhancing thermoelectric properties in TiNiSi structure-type semimetal ZrNiSi by dopingen_US
dc.typeArticleen_US
dc.contributor.departmentDept. of Physicsen_US
dc.identifier.sourcetitlePhysical Review Materialsen_US
dc.publication.originofpublisherForeignen_US
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