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Interplay of Cooper and Kondo singlet formations in high-TC cuprates

T. Sekitani·M. Naito·H. Sato·N. Miura
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Abstract

We performed high-field magnetotransport experiments up to 50 T on strained La1.85Sr0.15CuO4 films. Two films with different strain, one expansively strained with Tc ~ 26 K and the other compressively strained with Tc ~ 44 K, show a striking contrast in the normal-state transport: the former has a prominent low-temperature upturn while the latter has not. Identifying the low-temperature upturn as due to the Kondo effect, our experimental observations indicate that Cooper and Kondo singlet formations are competing in high- Tc cuprates: Kondo singlet formation hinders Cooper pair formation. Based on these results, we propose a new scenario for the electronic phase diagram of La2-xSrxCuO4. According to our scenario, underdoped insulating La2-xSrxCuO4 can be regarded as a "Kondo insulator".

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T. Sekitani, M. Naito, H. Sato, N. Miura. 2001-11-26. Interplay of Cooper and Kondo singlet formations in high-TC cuprates. https://arxiv.org/abs/cond-mat/0111422

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