Title: Understanding the role and interplay of heavy-hole and light-hole valence bands in the thermoelectric properties of PbSe

Abstract

The thermoelectric properties of PbSe have significantly improved in recent years reaching figures of merit ZT~1.6. The transport properties of the hole-doped high temperature thermoelectric material PbSe are particularly interesting and play a key role in this. Here, they were analyzed over wide temperature and hole concentration ranges. The special features observed in the variation of the experimental Seebeck coefficient and Hall coefficient can be accounted for within the framework of a two-band model. Two valence bands separated by a temperature dependent energy offset are considered. Furthermore, the extremum of the light-hole band has a density of states mass ~0.27m_o at room temperature. It is nonparabolic and anisotropic and can be described by the Kane model. The extremum of the heavy-hole band is isotropic and parabolic with a much larger density of states mass ~2.5m_o. We find that for heavily doped compositions, the high mass band contributes the Seebeck coefficient, even at room temperature. With rising temperature, holes are transferred from the light-hole to the heavy-hole branch, giving rise to the anomalous temperature dependent Hall coefficient, which is found peaked near ~650K. For Na-doped samples Pb_1–xNa_xSe for 0.01 ≤ x ≤ 0.03, the high thermopower values of 200–300μV/K at 900more » K arise from the heavy-hole band, which are responsible for the excellent thermoelectric performance of PbSe.« less

Authors:

Chasapis, Thomas C. ^[1]; Lee, Yeseul ^[1]; Hatzikraniotis, Euripides ^[2]; Paraskevopoulos, Konstantinos M. ^[2]; Chi, Hang ^[3]; Uher, Ctirad ^[3]; Kanatzidis, Mercouri G. ^[1]

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+ Show Author Affiliations

1. Northwestern Univ., Evanston, IL (United States)
2. Aristotle Univ. of Thessaloniki (Greece)
3. Univ. of Michigan, Ann Arbor, MI (United States)

Publication Date:

Sun Feb 15 00:00:00 EST 2015

Research Org.:

Energy Frontier Research Centers (EFRC) (United States). Revolutionary Materials for Solid State Energy Conversion (RMSSEC)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1370356

Alternate Identifier(s):

OSTI ID: 1181587

Grant/Contract Number:  

SC0001054

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review. B, Condensed Matter and Materials Physics

Additional Journal Information:

Journal Volume: 91; Journal Issue: 8; Related Information: RMSSEC partners with Michigan State University (lead); University of California, Los Angeles; University of Michigan; Northwestern University; Oak Ridge National Laboratory; Ohio State University; Wayne State University; Journal ID: ISSN 1098-0121

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE