Resistivity studies in the Kondo insulating system, FeSi1-xGex

Bharathi, A. ; Mani, Awadhesh ; Narasimha Rao, G. V. ; Sundar, C. S. ; Hariharan, Y. (1997) Resistivity studies in the Kondo insulating system, FeSi1-xGex Physica B: Condensed Matter, 240 (1-2). pp. 1-7. ISSN 0921-4526

Full text not available from this repository.

Official URL:

Related URL:


Electrical resistivity measurements have been carried out in the FeSi1-xGex system in the 1.4-300 K temperature range for 0.0≤x 0.25, the composition range in which the samples are monophasic. In FeSi, the resistance shows a two-step increase with decrease in temperature; the high-temperature region (200-100K) showing an activated semiconducting behaviour corresponding to a gap value, Δ, of 707 K. With Ge substitution at the Si site, the resistivity continues to show a semiconducting behaviour and the gap values obtained from the experimental data systematically decrease to 115 K for x=0.25. The observed decrease in Δ is discussed in conjuction with band-structure calculations. In FeSi and in the Ge substituted sample with x=0.05, the resistivity in the 5-50 K range could be fitted either to an activated behaviour with lower Δ or to the variable-range hopping mechanism. In the samples with x>0.05, the data in the 5-50 K region fits better to the variable-range hopping mechanism. Below 5 K, the resistance tends to saturate to a constant value in FeSi and the low-temperature saturation of resistance persists upon Ge substitution, possibly implying a metallic ground state as T→0.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Kondo Insulator; FeSi; Resistivity; Band Structure
ID Code:53263
Deposited On:05 Aug 2011 10:34
Last Modified:05 Aug 2011 10:34

Repository Staff Only: item control page