Cavity mode waves during terahertz radiation from rectangular Bi(2)Sr(2)CaCu(2)O(8 + δ) mesas

Area of Science:

• Condensed Matter Physics
• Superconductivity
• High-Temperature Superconductors

Background:

• Intrinsic Josephson junctions in cuprate superconductors exhibit complex radiation patterns.
• Understanding the origin of cavity modes is crucial for explaining observed radiation phenomena.

Purpose of the Study:

• To determine if cavity mode radiation in Bi(2)Sr(2)CaCu(2)O(8 + δ) mesas originates from waves along the length or width.
• To differentiate between standing and traveling wave models for cavity modes.

Main Methods:

• Analytical derivation of angular dependence for cavity modes.
• Fitting experimental data to models assuming incoherent combination of Josephson current and cavity magnetic surface current radiation.
• Analysis of specific mesa geometries (nl/2ω integral) to distinguish wave propagation directions.

Main Results:

• Both wave propagation along the length and width are equally probable explanations for the observed radiation.
• Analytical models successfully fit experimental data for a mesa with l/ω = 5.17.
• Standing cavity waves along the mesa length do not radiate in a specific plane for certain mesa dimensions.

Conclusions:

• The study provides insights into the nature of cavity modes in intrinsic Josephson junctions.
• Further experiments on specifically designed mesas are suggested to definitively resolve the direction of cavity wave formation.
• This research contributes to the understanding of electromagnetic phenomena in high-temperature superconductors.