Physics / Fizik
Permanent URI for this collectionhttps://hdl.handle.net/11147/6
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Article Citation - WoS: 6Citation - Scopus: 7Thin Film Like Terahertz Bolometric Detector on Bi2212 Single Crystal(Springer Verlag, 2016) Semerci, Tuğçe; Demirhan, Yasemin; Demirhan, Yasemin; Wang, Huabing; Özyüzer, Lütfi; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of TechnologyIn this study, we developed a microbolometer chip fabricated from high temperature superconducting Bi2Sr2CaCu2O8+δ (Bi2212) single crystals for the terahertz (THz) detection. For the manufacturing of the microbolometer chips, Bi2212 single crystals were transferred on substrate in the thin film like form and electron beam lithography, ion beam etching techniques were used. Resistance versus temperature behavior of the bolometer chips were performed by four probe technique in liquid nitrogen cryostat. Bi2212 microchips were integrated and characterized using in our custom-designed cryogenic bolometer system instead of expensive and massive cooling systems. The fabricated microchips significantly detected signals from the Stefan-Boltzmann lamp which includes a portion of THz radiation. The detected power and response time were studied for Bi2212 thin film like microbolometer chips. Our results demonstrated the feasibility of improved Bi2212 microchips could be used for bolometric detection for THz applications.Article Citation - WoS: 28Citation - Scopus: 29Eliashberg Analysis of Tunneling Experiments: Support for the Pairing Glue Hypothesis in Cuprate Superconductors(American Physical Society, 2011) Ahmadi, O.; Özyüzer, Lütfi; Zasadzinski, John F.; Miyakawa, Nobuaki; Özyüzer, Lütfi; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of TechnologyEvidence for the validity of the pairing glue interpretation of high temperature superconductivity is presented using a modified Eliashberg analysis of experimental superconductor-insulator-superconductor (SIS) tunneling data in B2Sr2CaCu2O8 (Bi2212) over a wide range of doping. This is accomplished by extracting detailed information on the diagonal and anomalous contributions to the quasiparticle self-energy. In particular, a comparison of the imaginary part of the anomalous self-energy ImΦ(ω) and the pairing glue spectral function α2F(ω) used in the model is consistent with Hubbard model simulations in the literature. In addition, the real part of the diagonal self-energy for optimal doped Bi2212 bears a strong resemblance to that obtained from photoemission experiments.Conference Object Citation - WoS: 4Citation - Scopus: 4Probing the Phase Diagram of Bi2sr2cacu 2o8+? With Tunneling Spectroscopy(Institute of Electrical and Electronics Engineers Inc., 2003) Özyüzer, Lütfi; Özyüzer, Lütfi; Gray, Kenneth E.; Hinks, David G.; Miyakawa, Nobuaki; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of TechnologyTunneling measurements are performed on Ca-rich single crystals of Bi 2Sr2CaCu2O8+δ (Bi2212), with various oxygen doping levels, using a novel point contact method. At 4.2 K, SIN and SIS tunnel junctions are obtained with well-defined quasiparticle peaks, robust dip and hump features and in some cases Josephson currents. The doping dependence of tunneling conductances of Ca-rich Bi2212 are analyzed and compared to stoichiometric Bi2212. A similar profile of energy gap vs. doping concentration is found although the Ca-rich samples have a slighly smaller optimum Tc and therefore smaller gap values for any doping level. The evolution of tunneling conductance peak height to background ratios with hole concentration are compared. For a given doping level, the Ca-rich spectra showed more broadened features compared to the stoichiometric counterparts, most likely due to increased disorder from the excess Ca. Comparison of the dip and hump features has provided some potential insights into their origins.