Correlation between superconductivity and in-plane resistivity in La_2-xSr_xCuO₄

Abstract

To investigate the correlation between the high-T c superconductivity and two-dimensional metallic properties, the in-plane resistivity ab of La 2Àx Sr x CuO 4 (LSCO) with x ¼ 0:06, 0.07, 0.08 and 0.22 has been measured under anisotropic high pressures up to 8.0 GPa. Although high pressure suppresses the orthorhombic distortion so as to contribute positively to T c , the inter-layer compression was found to bring about a kind of localization in the electronic state of the two-dimensional CuO 2 planes in the underdoped region. The collapse of two-dimensional metallic state probed by ab was confirmed to cause the superconductor-insulator transition in the under-doped cuprates. On the other hand, the overdoped cuprates lose superconductivity when the electronic structure changes from the two-dimensional metallic one to a strongly anisotropic but three-dimensional Fermi liquid system. The temperature dependence of ab is discussed in details in conjunction with T c both for the under-doped and overdoped LSCO.

Pressure-induced antiferromagnetism in UPt

“…Electric resistivity was measured by a standard four-probe method in the temperature range between 4.2 and 300 K. A cubic anvil device was used for generating pressure up to 8.0 GPa. 5,6…”

Superconductivity in under-doped La2−Sr CuO4 under pressure

“…13CE2002) from MEXT, Japan, and also supported by an aid fund from Energia. of single crystals taken from our previous reports [4,5]. The crosses are T T c of polycrystals estimated from the reported data [6].…”