Hostname: page-component-78c5997874-dh8gc Total loading time: 0 Render date: 2024-11-05T04:22:55.158Z Has data issue: false hasContentIssue false
  • English
  • Français

Crystal structure and thermoelectric properties of the incommensurate chimney–ladder compound RhGeγ (γ ∼ 1.293)

Published online by Cambridge University Press:  01 June 2015

Yuzuru Miyazaki ,
Takaki Nakajo ,
Yuta Kikuchi  and
Kei Hayashi
Yuzuru Miyazaki*
Affiliation:
Department of Applied Physics, Graduate School of Engineering, Tohoku University, Aoba-ku, Sendai 980-8579, Japan
Takaki Nakajo
Affiliation:
Department of Applied Physics, Graduate School of Engineering, Tohoku University, Aoba-ku, Sendai 980-8579, Japan
Yuta Kikuchi
Affiliation:
Department of Applied Physics, Graduate School of Engineering, Tohoku University, Aoba-ku, Sendai 980-8579, Japan
Kei Hayashi
Affiliation:
Department of Applied Physics, Graduate School of Engineering, Tohoku University, Aoba-ku, Sendai 980-8579, Japan
*
a)Address all correspondence to this author. e-mail: [email protected]
Get access

Abstract

The (3 + 1)-dimensional crystal structure of the Nowotny chimney–ladder compound Rh17Ge22 was revealed using powder x-ray diffraction technique. As in the case of the higher manganese silicide MnSiγ (known as Mn11Si19, etc.), this germanide consists of two tetragonal subsystems of [Rh] and [Ge] with an irrational c-axis ratio γ = cRh/cGe, and hence the structural formula can be represented as RhGeγ. As expected from first-principles calculations of the approximate structure and the valence electron count, n-type (negative Seebeck coefficient) conduction was experimentally confirmed over the whole temperature range of 333–984 K. Although the absolute value of the Seebeck coefficient was limited to |S| ≤ 53 μV/K, a high electrical conductivity (σ = 4.8 × 103 S/cm) yielded a reasonable power factor of S2σ ∼ 1 mW/K2 m above 600 K. A maximum dimensionless figure-of-merit of ∼0.1 at 900 K was expected using thermal conductivity data of a sintered pellet.

Keywords

thermoelectricitycrystallographic structureelectronic structure
Type
Invited Article
Information
Journal of Materials Research , Volume 30 , Issue 17: Focus Issue: Advances in Thermoelectric Materials II , 14 September 2015 , pp. 2611 - 2617
Copyright
Copyright © Materials Research Society 2015 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Nowotny, H.: Crystal Chemistry of Transition Element Defect Silicides and Related Compounds. In The Chemistry of Extended Defects in Non-metallic Solids, Eyring, L. and O'Keeffe, M. eds. (North Holland, Amsterdam, 1970); pp. 227.Google Scholar
Springborg, M. and Fischer, R.: Electronic structures of three semiconducting intermetallics: RuAl2, RuGa2, and OsAl2. J. Phys. Condens. Matter 10, 701 (1998).CrossRefGoogle Scholar
Miyazaki, Y., Saito, Y., Hayashi, K., Yubuta, K., and Kajitani, T.: Preparation and thermoelectric properties of a chimney-ladder (Mn1-xFex)Siγ (γ ∼ 1.7) solid solution. Jpn. J. Appl. Phys. 50, 035804 (2011).CrossRefGoogle Scholar
Fedorov, M.I. and Zaitsev, V.K.: Thermoelectrics of Transition Metal Silicides. In Thermoelectrics Handbook, Rowe, D.M., ed. (CRC Press, Boca Raton, 2006); pp. 31–33.Google Scholar
Miyazaki, Y. and Kikuchi, Y.: Higher Manganese Silicide, MnSig. In Thermoelectric Nanomaterials. Springer Series in Materials Science, Koumoto, K. and Mori, T. eds. (Springer, Berlin Heidelberg, 2013); pp. 141–156.Google Scholar
Jeitschko, W. and Parthé, E.: The crystal structure of Rh17Ge22, an example of a new kind of electron compound. Acta Cryst. 22, 417 (1967).CrossRefGoogle Scholar
Miyazaki, Y., Igarashi, D., Hayashi, K., Kajitani, T., and Yubuta, K.: Modulated crystal structure of chimney-ladder higher manganese silicides MnSiγ. Phys. Rev. B 78, 214104 (2008).CrossRefGoogle Scholar
Petricek, V., Dusek, M., and Palatinus, L.: Crystallographic Computing System Jana2006 (Institute of Physics, Praha, Czech Republic, 2006).Google Scholar
Momma, K. and Izumi, F.: VESTA a three-dimensional visualization system for electronic and structural analysis. J. Appl. Cryst. 41, 653 (2008).CrossRefGoogle Scholar
Blaha, P., Schwarz, K., Madsen, G.K.H., Kvasnicka, D., and Luitz, J.: WIEN2k an Augumented Plane Wave + Local Orbital Program for Calculating Crystal Properties (K. Schwarz, Techn, Univ., Wien, Austria, 2001).Google Scholar
Perdew, J.P., Burke, K., and Ernzerhof, M.: Generalized gradient approximation made simple. In Phys. Rev. Lett. 77, 3865 (1996).Google Scholar
Miyazaki, Y.: Superspace Group Approach to the Crystal Structure of Thermoelectric Higher Manganese Silicides MnSig. In Neutron Diffraction, Khidirov, I. ed. (InTech, Rijeka, 2012); pp. 231.Google Scholar
Rohrer, F.E., Lind, H., Eriksson, L., Larsson, A.K., and Lidin, S.: On the question of commensurability – The Nowotny chimney-ladder structures revisited. Z. Kristallogr. 215, 650 (2000).Google Scholar
Rohrer, F.E., Lind, H., Eriksson, L., Larsson, A-K., and Lidin, S.: Incommensurately modulated Nowotny chimney-ladder phases Cr1-xMoxGe∼1.75 with x = 0.65 and 0.84. Z. Kristallogr. 216, 190 (2001).CrossRefGoogle Scholar
Inoue, T., Chikazumi, S., Nagasaki, S. and Tanuma, S. eds.: Agne Periodic Table (AGNE Technology Center, Tokyo, 2001).Google Scholar
Snyder, G.J. and Ursell, T.S.: Thermoelectric efficiency and compatibility. Phys. Rev. Lett. 91, 148301 (2003).CrossRefGoogle ScholarPubMed