Linewidth dependence of coherent terahertz emission from Bi sub(2)Sr sub(2) CaCu sub(2)O sub(8) intrinsic Josephson junction stacks in the hot-spot regime

• Published in: Physical review. B, Condensed matter and materials physics Condensed matter and materials physics, 2012-08, Vol.86 (6)
• Main Authors: Li, Mengyue, Yuan, Jie, Kinev, Nickolay, Li, Jun, Gross, Boris, Guenon, Stefan, Ishii, Akira, Hirata, Kazuto, Hatano, Takeshi, Koelle, Dieter, Kleiner, Reinhold, Koshelets, Valery P, Wang, Huabing, Wu, Peiheng
• Format: Article
• Language: English
• Subjects: Bias; BISMUTH OXIDE; Condensed matter; COPPER OXIDE; CUPROUS OXIDE; Electron paramagnetic resonance; Hot spots; Josephson junctions; STACKS; SUPERCONDUCTORS; Synchronism
• ISSN: 1098-0121; 1550-235X

We report on measurements of the linewidth Delta [functionof] of terahertz radiation emitted from intrinsic Josephson junction stacks, using a Nb/AlN/NbN integrated receiver for detection. Previous resolution-limited measurements indicated that Delta [functionof] may be below 1 GHz-much smaller than expected from a purely cavity-induced synchronization. While at low bias we found Delta [functionof] to be not smaller than ~500 MHz, at high bias, where a hot spot coexists with regions which are still superconducting, Delta [functionof] turned out to be as narrow as 23 MHz. We attribute this to the hot spot acting as a synchronizing element. Delta [functionof] decreases with increasing bath temperature, a behavior reminiscent of motional narrowing in NMR or electron spin resonance (ESR), but hard to explain in standard electrodynamic models of Josephson junctions.