Gap-like feature in the normal state of $\bf{X(Fe_{1-x}Co_x)_2As_2}$, $\bf{X=Ba,Sr}$ and $\bf{Fe_{1+y}Te}$ revealed by Point Contact Spectroscopy

H. Z. Arham; C. R. Hunt; W. K. Park; J. Gillett; S. D. Das; S. E. Sebastian; Z. J. Xu; J. S. Wen; Z. W. Lin; Q. Li; G. Gu; A. Thaler; S. L. Budko; P. C. Canfield; L. H. Greene

doi:10.1088/1742-6596/400/2/022001

arXiv · 1108.2749

Gap-like feature in the normal state of $\bf{X(Fe_{1-x}Co_x)_2As_2}$, $\bf{X=Ba,Sr}$ and $\bf{Fe_{1+y}Te}$ revealed by Point Contact Spectroscopy

H. Z. Arham·C. R. Hunt·W. K. Park·J. Gillett·S. D. Das·S. E. Sebastian·Z. J. Xu·J. S. Wen·Z. W. Lin·Q. Li·G. Gu·A. Thaler·S. L. Budko·P. C. Canfield·L. H. Greene

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Abstract

Point contact spectroscopy reveals a gap-like feature above the magnetic and structural transition temperatures for underdoped $Ba(Fe_{1-x}Co_x)_2As_2$, $SrFe_2As_2$ and $Fe_{1+y}Te$. The conductance spectrum starts showing an enhancement at temperatures as high as 177 K for $BaFe_2As_2$ ($T_N$ $\sim$ 132 K) and 250 K for $SrFe_2As_2$ ($T_N$ $\sim$ 192 K). Possible origins for this enhancement are discussed in light of recent experimental claims of nematicity in these materials. We construct a modified phase diagram for Co-doped Ba122 showing a gap-like feature existing above $T_N$ and $T_S$ for the underdoped regime.

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H. Z. Arham, C. R. Hunt, W. K. Park, J. Gillett, S. D. Das, S. E. Sebastian, Z. J. Xu, J. S. Wen, Z. W. Lin, Q. Li, G. Gu, A. Thaler, S. L. Budko, P. C. Canfield, L. H. Greene. 2011-08-13. Gap-like feature in the normal state of $\bf{X(Fe_{1-x}Co_x)_2As_2}$, $\bf{X=Ba,Sr}$ and $\bf{Fe_{1+y}Te}$ revealed by Point Contact Spectroscopy. https://doi.org/10.1088/1742-6596/400/2/022001

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