TY - JOUR
T1 - Large phonon drag thermopower boosted by massive electrons and phonon leaking in LaAlO3/LaNiO3/LaAlO3heterostructure
AU - Kimura, Masatoshi
AU - He, Xinyi
AU - Katase, Takayoshi
AU - Tadano, Terumasa
AU - Tomczak, Jan M.
AU - Minohara, Makoto
AU - Aso, Ryotaro
AU - Yoshida, Hideto
AU - Ide, Keisuke
AU - Ueda, Shigenori
AU - Hiramatsu, Hidenori
AU - Kumigashira, Hiroshi
AU - Hosono, Hideo
AU - Kamiya, Toshio
N1 - Funding Information:
The authors thank Dr. Y. Nomura (RIKEN, Japan) for valuable discussions. This work was supported by PRESTO, Japan Science and Technology Agency (Grant No. JPMJPR16R1), and the Ministry of Education, Culture, Sports, Science and Technology (MEXT) though the Element Strategy Initiative to Form Core Research Center (Grant No. JPMXP0112101001). TEM observation was supported by “Dynamic Alliance for Open Innovation Bridging Human, Environment and Materials” from MEXT. The HAXPES measurements were performed with the approval of the NIMS Synchrotron X-ray Station (Proposal Nos. 2018A4701, 2018B4701 and 2020A4701). T. Katase was supported by the Japan Society for the Promotion of Science (JSPS) through Grants-in-Aid for Scientific Research (B) (Grant No. 19H02425) and a Grant-in-Aid for Challenging Research (Exploratory) (Grant No. 20K21075). T.T. was supported by the JSPS through a Grant-in-Aid for Scientific Research (S) (No. 16H06345). J.M.T. was supported by the Austrian Science Fund (FWF) through project P 30213. H. Hiramatsu was supported by the JSPS through Grants-in-Aid for Scientific Research (A) (No. 21H04612).
Publisher Copyright:
© 2021 American Chemical Society.
PY - 2021/11/10
Y1 - 2021/11/10
N2 - An unusually large thermopower (S) enhancement is induced by heterostructuring thin films of the strongly correlated electron oxide LaNiO3. The phonon-drag effect, which is not observed in bulk LaNiO3, enhances S for thin films compressively strained by LaAlO3 substrates. By a reduction in the layer thickness down to three unit cells and subsequent LaAlO3 surface termination, a 10 times S enhancement over the bulk value is observed due to large phonon drag S (Sg), and the Sg contribution to the total S occurs over a much wider temperature range up to 220 K. The Sg enhancement originates from the coupling of lattice vibration to the d electrons with large effective mass in the compressively strained ultrathin LaNiO3, and the electron-phonon interaction is largely enhanced by the phonon leakage from the LaAlO3 substrate and the capping layer. The transition-metal oxide heterostructures emerge as a new playground to manipulate electronic and phononic properties in the quest for high-performance thermoelectrics.
AB - An unusually large thermopower (S) enhancement is induced by heterostructuring thin films of the strongly correlated electron oxide LaNiO3. The phonon-drag effect, which is not observed in bulk LaNiO3, enhances S for thin films compressively strained by LaAlO3 substrates. By a reduction in the layer thickness down to three unit cells and subsequent LaAlO3 surface termination, a 10 times S enhancement over the bulk value is observed due to large phonon drag S (Sg), and the Sg contribution to the total S occurs over a much wider temperature range up to 220 K. The Sg enhancement originates from the coupling of lattice vibration to the d electrons with large effective mass in the compressively strained ultrathin LaNiO3, and the electron-phonon interaction is largely enhanced by the phonon leakage from the LaAlO3 substrate and the capping layer. The transition-metal oxide heterostructures emerge as a new playground to manipulate electronic and phononic properties in the quest for high-performance thermoelectrics.
KW - Strongly correlated electron oxide
KW - Thermoelectrics
KW - Thin film heterostructure
KW - Transition-metal oxide
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U2 - 10.1021/acs.nanolett.1c03143
DO - 10.1021/acs.nanolett.1c03143
M3 - Article
C2 - 34709840
AN - SCOPUS:85118892814
SN - 1530-6984
VL - 21
SP - 9240
EP - 9246
JO - Nano Letters
JF - Nano Letters
IS - 21
ER -