Abstract-Linewidth dependence of coherent terahertz emission from Bi2Sr2CaCu2O8 intrinsic Josephson junction stacks in the hot-spot regime

http://prb.aps.org/abstract/PRB/v86/i6/e060505
Mengyue Li^1,2, Jie Yuan^2,3,*, Nickolay Kinev⁴, Jun Li^2,5, Boris Gross⁶, Stefan Guénon⁶, Akira Ishii², Kazuto Hirata², Takeshi Hatano², Dieter Koelle⁶, Reinhold Kleiner⁶, Valery P. Koshelets⁴, Huabing Wang^1,2,†, and Peiheng Wu^1 
1Research Institute of Superconductor Electronics, Nanjing University, Nanjing 210093, China
²National Institute for Materials Science, Tsukuba 3050047, Japan
³Department of Applied Physics, Wuhan University of Science and Technology, Wuhan 430081, China
⁴Kotel'nikov Institute of Radio Engineering and Electronics, Moscow 125009, Russia
⁵Hokkaido University, Hokkaido 0600810, Japan
⁶Physikalisches Institut and Center for Collective Quantum Phenomena in LISA⁺, Universität Tübingen, D-72076 Tübingen, Germany

 Received 3 April 2012; revised 20 July 2012; published 8 August 2012

We report on measurements of the linewidth Δf of terahertz radiation emitted from intrinsic Josephson junction stacks, using a Nb/AlN/NbN integrated receiver for detection. Previous resolution-limited measurements indicated that Δf may be below 1 GHz—much smaller than expected from a purely cavity-induced synchronization. While at low bias we found Δf to be not smaller than ∼500 MHz, at high bias, where a hot spot coexists with regions which are still superconducting, Δfturned out to be as narrow as 23 MHz. We attribute this to the hot spot acting as a synchronizing element. Δf 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.

©2012 American Physical Society

URL:

http://link.aps.org/doi/10.1103/PhysRevB.86.060505

DOI:

10.1103/PhysRevB.86.060505

PACS:

74.50.+r, 74.72.-h, 85.25.Cp

^*phy.wust@gmail.com

^†hbwang1000@gmail.com