Abbreviated Journal Title
Phys. Rev. B
INTRINSIC JOSEPHSON-JUNCTIONS; SCANNING-ELECTRON-MICROSCOPY; T-C; SILICON-CARBIDE; RESOLUTION; HOTSPOTS; RADIATION; FILMS; Physics, Condensed Matter
From the photoluminescence of SiC microcrystals uniformly covering a rectangular mesa of the high transition temperature T-c superconductor Bi2Sr2CaCu2O8+delta, the local surface temperature T(r) was directly measured during simultaneous sub-THz emission from the N similar to 10(3) intrinsic Josephson junctions (IJJs) in the mesa. At high bias currents I and low bath temperatures T-bath less than or similar to 35 K, the center of a large elliptical hot spot with T(r) > T-c jumps dramatically with little current-voltage characteristic changes. The hot spot does not alter the ubiquitous primary and secondary emission conditions: the ac-Josephson relation and the electromagnetic cavity resonance excitation, respectively. Since the most intense sub-THz emission was observed for high T-bath greater than or similar to 50 K in the low I bias regime where hot spots are absent, hot spots cannot provide the primary mechanisms for increasing the output power, the tunability, or promoting the synchronization of the N IJJs for the sub-THz emission, but can at best coexist nonmutualistically with the emission. No T(r) standing waves were observed.
Physical Review B
Minami, Hidetoshi; Watanabe, Chiharu; Sato, Kota; Sekimoto, Shunsuke; Yamamoto, Takashi; Kashiwagi, Takanari; Klemm, Richard A.; and Kadowaki, Kazuo, "Local SiC photoluminescence evidence of hot spot formation and sub-THz coherent emission from a rectangular Bi2Sr2CaCu2O8+delta mesa" (2014). Faculty Bibliography 2010s. 5838.