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NANOSYSTEMS: PHYSICS, CHEMISTRY, MATHEMATICS, 2015, 6 (6), P. 803-824

Intra pseudogap- and superconductivy-pair spin and charge fluctuations and underdome metal-insulator (fermion-boson)-crossover phenomena as keystones of cuprate physics

B. Abdullaev – Institute of Applied Physics, National University of Uzbekistan, Tashkent 100174, Uzbekistan; bakhodir.abdullaeff@yandex.ru
D. B. Abdullaev- Institute of Applied Physics, National University of Uzbekistan, Tashkent 100174, Uzbekistan
C. -H. Park – Research Center for Dielectric and Advanced Matter Physics, Department of Physics, Pusan National University, 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735, Korea; cpark@pusan.ac.kr
M. M. Musakhanov – National University of Uzbekistan, Tashkent 100174, Uzbekistan; yousufmm@list.ru

The most intriguing observation of cuprate experiments is most likely the metal-insulator-crossover (MIC), seen in the underdome region of the temperature-doping phase diagram for copper-oxides under a strong magnetic eld, when superconductivity is suppressed. This MIC, which results in such phenomena as heat conductivity downturn, anomalous Lorentz ratio, nonlinear entropy, insulating ground state, nematicity- and stripe-phases and Fermi pockets, reveals the nonconventional dielectric property of the pseudogap-normal phase. Since conventional superconductivity appears from a conducting normal phase, the understanding of how superconductivity arises from an insulating state becomes a fundamental problem and thus the keystone for all of cuprate physics. Recently, in interpreting the physics of visualization in scanning tunneling microscopy (STM) real space nanoregions (NRs), which exhibit an energy gap, we have succeeded in understanding that the minimum size for these NRs provides pseudogap and superconductivity pairs, which are single bosons. In this work, we discuss the intra-particle magnetic spin and charge fluctuations of these bosons, observed recently in hidden magnetic order and STM experiments. We nd that all the mentioned MIC phenomena can be obtained in the Coulomb single boson and single fermion two liquid model, which we recently developed, and the MIC is a crossover of sample percolating NRs of single fermions into those of single bosons.

Keywords: high critical temperature superconductivity, cuprate, metal-insulator-crossover, temperature-doping phase diagram, heat conductivity downturn, anomalous Lorentz ratio, nonlinear entropy, insulating ground state, stripe phase, Fermi pocket.

PACS 74.72.-h, 74.20.Mn, 74.25.Fy, 74.25.Bt, 74.25.Jb, 74.25.Ha

DOI 10.17586/2220-8054-2015-6-6-803-824

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