Dynamic Control of Temperature Distributions in Stacks of Intrinsic Josephson Junctions inBi2Sr2CaCu2

Abstract

We study the universal relationship between the hot-spot size and the intensity of terahertz emission from intrinsic Josephson junctions by dynamically controlling the temperature distributions in mesas of Bi 2 Sr 2 CaCu 2 O 8þδ . The uniform current bias leads to a significant increase in local temperature compared to the nonuniform current bias. The thermal response of emission differs between the high-and low-bias regimes. We find a strong positive correlation between the emission intensity and the volume of the superconducting parts in the emitting stack. We identify the remarkable increase in the emission intensity by up to 20% by eliminating the excess Joule heat from the mesa.

Three-Dimensional Simulations of the Electrothermal and Terahertz Emission Properties ofBi2Sr2CaCu2Rudau1, Wieland2, Langer3 et al. 2016Phys. Rev. Applied290270View full textAdd to dashboardCite

“…For sufficiently low bias currents, the temperature rises only slightly to values above the bath temperature T bath and the voltage V across the stack increases with increasing bias current I. With increasing I and input power the currentvoltage characteristics (IVCs) start to back-bend and, at some bias current in the back-bending region, a hot spot forms in the stack 3,6,8,13,18,[21][22][23]25,26,34,68 , creating a region heated to temperatures above the critical temperature T c . Similar effects also occur in other systems 69,70 .…”

Temperature dependence of terahertz emission by an asymmetric intrinsic Josephson junction device

“…13 More recently, we have reported that the hotspots are detrimental for emission intensities. 14 The emission frequency f e is tuned by changing either the bias current or bath temperature T b . Benseman et al investigated the temperature dependence of the emission frequency in asymmetric device configuration, namely, a superconducting substrate overlain with a trapezoidal stack.…”

Applications using high-Tc superconducting terahertz emitters

“…The unique (sub-) THz source based on a single-crystalline mesa structure of the high transition-temperature T c superconductor Bi 2 Sr 2 CaCu 2 O 8+ δ (Bi2212) was first reported in 200716, and its subsequent development has proceeded rapidly171819202122232425262728293031323334353637383940414243444546. Output radiation powers of a few tens of μ W have been consistently achieved from single conventional mesas3743,44, and of about 600  μ W was reported from a synchronized conventional three-mesa array45, and the radiation frequency could be varied almost continuously between 0.3 and 2.4 THz from a stand-alone mesa sandwich device46.…”