The maximum dimensionless figure of merit, ZTmax, as a function of the chemical potential of the narrow-bandgap intermetallic compound RuGa2 was calculated by using the Boltzmann transport equation with a simple rigid band approach under the constant relaxation time assumption. The calculation, including the effect of the group velocity, indicates that ZTmax over unity would be achieved by electron doping rather than hole doping. Based on this calculation, the effects of Ir substitution for Ru on the thermoelectric properties for RuGa2 have been investigated in the temperature range from 373 K to 973 K. Indeed, a relatively large ZT value of 0.31 for n-type material was obtained in the nominal composition of Ir3.0Ru30.4Ga66.6. The discussion includes the validity of the rigid band approximation and further enhancement of ZT from theoretical and experimental aspects.
REFERENCES
1.
G. J.
Snyder
and E. S.
Toberer
, Nature Mater.
7
, 105
(2008
).2.
G. D.
Mahan
and J. O.
Sofo
, Proc. Natl. Acad. Sci. U. S. A.
93
, 7436
(1996
).3.
J. S.
Tse
and D. D.
Klug
, Thermoelectrics Handbook Macro to Nano
, edited by D. M.
Rowe
(Taylor & Francis
, Boca Raton
, 2006
), Chap. 8-1-27.4.
T.
Takeuchi
, Mater. Trans.
50
, 2359
(2009
).5.
M. A.
Avila
, K.
Suekuni
, K.
Umeo
, H.
Fukuoka
, S.
Yamanaka
, and T.
Takabatake
, Appl. Phys. Lett.
92
, 041901
(2008
).6.
Y.
Kono
, N.
Ohya
, T.
Taguchi
, K.
Suekuni
, T.
Takabatake
, S.
Yamamoto
, and K.
Akai
, J. Appl. Phys.
107
, 123720
(2010
).7.
Y.
Nishino
, H.
Sumi
, and U.
Mizutani
, Phys. Rev. B
71
, 094425
(2005
).8.
Y.
Takagiwa
, T.
Kamimura
, J. T.
Okada
, and K.
Kimura
, J. Electron. Mater.
39
, 1885
(2010
).9.
S.
Takahashi
, H.
Muta
, K.
Kurosaki
, and S.
Yamanaka
, J. Alloys Compd.
493
, 17
(2010
).10.
Y.
Takagiwa
, Y.
Matsubayashi
, A.
Suzumura
, J. T.
Okada
, and K.
Kimura
, Mater. Trans.
51
, 988
(2010
).11.
Y.
Amagai
, A.
Yamamoto
, C.-H.
Lee
, H.
Ohara
, K.
Ueno
, T.
Iida
, and Y.
Takanashi
, Papers of Technical Meeting on Frontier Technology and Engineering
(IEE
Japan
, vol. FTE-05
, 2005
), pp. 41
–46
.12.
Y.
Takagiwa
, J. T.
Okada
, and K.
Kimura
, J. Alloys Compd.
507
, 364
(2010
).13.
Y.
Takagiwa
, J. T.
Okada
, and K.
Kimura
, J. Electron. Mater.
40
, 1067
(2011
).14.
V.
Ponnambalam
, G.
Lehr
, and D. T.
Morelli
, J. Mater. Res.
26
, 1907
(2011
).15.
M.
Wagner
, R.
Cardoso-Gil
, N.
Oeschler
, H.
Rosner
, and Yu.
Grin
, J. Mater. Res.
26
, 1886
(2011
).16.
D.
Kasinathan
, M.
Wagner
, K.
Koepernik
, R.
Cardoso-Gil
, Yu.
Grin
, and H.
Rosner
, Phys. Rev. B
85
, 035207
(2012
).17.
Y.
Takagiwa
, K.
Kitahara
, Y.
Matsubayashi
, and K.
Kimura
, J. Appl. Phys.
111
, 123707
(2012
).18.
D. N.
Manh
, G. T.
de Laissardiere
, J. P.
Julien
, D.
Mayou
, and F.
Cyrot-Lackmann
, Solid State Commun.
82
, 329
(1992
).19.
M.
Weinert
and R. E.
Watson
, Phys. Rev. B
58
, 9732
(1998
).20.
D.
Bogdanov
, K.
Winzer
, I. A.
Nekrasov
, and T.
Pruschke
, J. Phys.: Condens. Matter
19
, 232202
(2007
).21.
P.
Blaha
, K.
Schwarz
, G. K. H.
Madsen
, D.
Kvasnicka
, and J.
Luitz
, WIEN2k, An Augmented Plane Wave + Local Orbitals Programs for Calculating Crystal Properties
(Techn. Universität Wien
, Austria
, 2001
).22.
T. J.
Scheidemantel
, C.
Ambrosch-Draxl
, T.
Thonhauser
, J. V.
Badding
, and J. O.
Sofo
, Phys. Rev. B
68
, 125210
(2003
).23.
C.
Ambrosch-Draxl
and J. O.
Sofo
, Compt. Phys. Commun.
175
, 1
(2006
).24.
D. G.
Cahill
, S. K.
Watson
, and R. O.
Pohl
, Phys. Rev. B
46
, 6131
(1992
).25.
D. G.
Cahill
and R. O.
Pohl
, Solid State Commun.
70
, 927
(1989
).26.
A.
Zevalkink
, E. S.
Toberer
, T.
Bleith
, E.
Flage-Larsen
, and G. J.
Snyder
, J. Appl. Phys.
110
, 013721
(2011
).27.
Y.
Takagiwa
, T.
Kamimura
, S.
Hosoi
, J. T.
Okada
, and K.
Kimura
, J. Appl. Phys.
104
, 073721
(2008
).28.
Y.
Takagiwa
, T.
Kamimura
, S.
Hosoi
, J. T.
Okada
, and K.
Kimura
, Z. Kristallogr.
224
, 79
(2009
).29.
Y.
Amagai
, A.
Yamamoto
, T.
Iida
, and Y.
Takanashi
, J. Appl. Phys.
96
, 5644
(2004
).30.
H.
Akai
, J. Phys. Soc. Jpn.
51
, 468
(1982
);H.
Akai
, J. Phys.: Condens. Matter
1
, 8045
(1989
);M.
Schröter
, H.
Ebert
, H.
Akai
, P.
Entel
, E.
Hoffmann
, and G. G.
Reddy
, Phys. Rev. B
52
, 188
(1995
).31.
C. M.
Jaworski
, J.
Tobola
, E. M.
Levin
, K.
Schmidt-Rohr
, and J. P.
Heremans
, Phys. Rev. B
80
, 125208
(2009
).32.
Y.
Takagiwa
, Y.
Pei
, G.
Pomrehn
, and G. J.
Snyder
, Appl. Phys. Lett.
101
, 092102
(2012
).33.
X.
Yan
, G.
Joshi
, W.
Liu
, Y.
Lan
, H.
Wang
, S.
Lee
, J. W.
Simonson
, S. J.
Poon
, T. M.
Tritt
, G.
Chen
, and Z. F.
Ren
, Nano Lett.
11
, 556
(2011
).34.
D. J.
Singh
, Phys. Rev. B
81
, 195217
(2010
).© 2013 American Institute of Physics.
2013
American Institute of Physics
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