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Title: Device-quality tunnel junctions on the high {Tc} superconductor HgBa{sub 2}CuO{sub 4+{delta}}

Conference ·
OSTI ID:10106817
 [1]; ; ; ; ;  [2]
  1. Illinois Institute of Technology, Chicago, IL (United States)
  2. Argonne National Lab., IL (United States)

SIN and SIS tunnel junction devices (e.g. photon detectors, logic elements) require quasiparticle characteristics that exhibit sharp current onsets at the gap voltage and very low sub-gap conductances. Progress is reported on the development of such junctions on High Tc cuprates using mechanical point contacts. In general, these contacts display the optimum characteristics that can be obtained from HTS native-surface tunnel barriers. Most cuprates display a sub-gap conductance which monotonically increases with voltage about the minimum value at zero bias. However, tunneling data of unusually high quality have been obtained for the recently discovered Hg-based cuprate, HgBa{sub 2}CuO{sub 4} (T{sub c}=96K). SIS{prime} tunneling data using a Nb tip are presented which exhibit very low and flat sub-gap conductances and sharp conductance peaks as expected from a BCS density of states. These results are slightly improved over earlier published results with SIN junctions. Use of the experimental data to simulate the performance of a quasiparticle mixer demonstrates that noise temperatures approaching the quantum limit are possible for SIS and SIN mixers in the range 1-5 THz.

Research Organization:
Argonne National Lab., IL (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States); National Science Foundation, Washington, DC (United States)
DOE Contract Number:
W-31109-ENG-38
OSTI ID:
10106817
Report Number(s):
ANL/MSD/CP-84398; CONF-940926-3; ON: DE95004646; CNN: Contract DMR 91-20000; TRN: 95:000840
Resource Relation:
Conference: 7. conference on superconductivity and applications,Buffalo, NY (United States),7-9 Sep 1994; Other Information: PBD: [1995]
Country of Publication:
United States
Language:
English