Match!
H. F. Hess
Bell Labs
9Publications
6H-index
794Citations
Publications 9
Newest
#1Hans D. Hallen (NCSU: North Carolina State University)H-Index: 21
#2Albert M. Chang (Bell Labs)H-Index: 31
Last.H. F. Hess (Bell Labs)H-Index: 6
view all 6 authors...
Abstract We report direct, high resolution images of the magnetic field above a superconducting wire grid as applied flux penetrates into an initially empty state or into a state with half the plaquettes containing a magnetic quantum. We find two qualitatively different initial approaches to equilibrium: in wide structures for the former, or with long, linear structures for the latter case. In the approach to an empty state, we observe the formation of residual quasi-bound magnetic vortex/anti-v...
1 CitationsSource
#1H. F. Hess (Bell Labs)H-Index: 6
#2Eric Betzig (Bell Labs)H-Index: 53
Last.K. W. West (Bell Labs)H-Index: 52
view all 5 authors...
Luminescent centers with sharp (<0.07 millielectron volt), spectrally distinct emission lines were imaged in a GaAs/AIGaAs quantum well by means of low-temperature near-field scanning optical microscopy. Temperature, magnetic field, and linewidth measurements establish that these centers arise from excitons laterally localized at interface fluctuations. For sufficiently narrow wells, virtually all emission originates from such centers. Near-field microscopy/spectroscopy provides a means to acces...
370 CitationsSource
#1H. F. Hess (Bell Labs)H-Index: 6
#2Eric BetzigH-Index: 53
Last.K. W. WestH-Index: 52
view all 5 authors...
Summary form only given. Low temperature near-field scanning optical microscopy/spectroscopy has proven useful in characterization of quantum confined semiconductor structures even to the extent of revealing the individual optically active quantum constituents of such a system. Specifically, sharp (<0.07 meV), spectrally distinct emission lines of a GaAs/AlGaAs quantum well can be imaged at a specific spatial location, or as a spectral evolution image as the probe is scanned along a line across ...
Source
#1Hans D. HallenH-Index: 21
#2Seshadri RH-Index: 1
Last.H. F. HessH-Index: 6
view all 8 authors...
We report direct observations of vortices in a square superconducting wire grid imaged using scanning Hall probe microscopy. Real space images of vortex configurations are obtained as a function of the flux per unit cell f by measuring the local magnetic field just above the sample. At f=1/2 we observe domains of the checkerboard ground state. As f is reduced from 1/2 to 1/3 vacancies first penetrate the grain boundaries and then the checkerboard domains. Near f=-1/3 we observe domains of the 1/...
38 CitationsSource
#1Hans D. Hallen (Bell Labs)H-Index: 21
#2H. F. Hess (Bell Labs)H-Index: 6
Last.David B. Mitzi (IBM)H-Index: 72
view all 6 authors...
A high resolution scanning Hall probe microscope is used to spatially resolve vortices in high temperature superconducting Bi2Sr2CaCu2O8+(delta) crystals. We observe a partially ordered vortex lattice at several different applied magnetic fields and temperatures. At higher temperatures, a limited amount of vortex re-arrangement is observed, but most vortices remain fixed for periods long compared to the imaging time of several hours even at temperatures as high as 75 degree(s)K (the superconduct...
1 CitationsSource
#1Albert M. Chang (Bell Labs)H-Index: 31
#2Hans D. Hallen (Bell Labs)H-Index: 21
Last.Tseng Yuan Chang (Bell Labs)H-Index: 29
view all 7 authors...
A high-resolution scanning Hall-probe microscope is used to spatially resolve vortices in high-temperature superconducting La1.85Sr0.15CuO4 films. At low magnetic fields, a disordered vortex arrangement is observed. A fit to the surface field of an individual vortex is consistent with one flux quantum, and is used to determine the local penetration depth and its temperature dependence. At higher fields, magnetic fluctuations are observed and compared to a collective pinning model. For films grow...
33 CitationsSource
#1Albert M. Chang (Bell Labs)H-Index: 31
#2Hans D. Hallen (Bell Labs)H-Index: 21
Last.Tseng Yuan Chang (Bell Labs)H-Index: 29
view all 10 authors...
We describe the implementation of a scanning Hall probe microscope of outstanding magnetic field sensitivity (∼0.1 G) and unprecedented spatial resolution (∼0.35 μm) to detect surface magnetic fields at close proximity to a sample. Our microscope combines the advantages of a submicron Hall probe fabricated on a GaAs/Al0.3Ga0.7As heterostructure chip and the scanning tunneling microscopy technique for precise positioning. We demonstrate its usefulness by imaging individual vortices in high Tc La1...
278 CitationsSource
#1J. S. Weiner (Bell Labs)H-Index: 22
#2H. F. Hess (Bell Labs)H-Index: 6
Last.M. Ranade (SC: University of Southern California)H-Index: 1
view all 7 authors...
We demonstrate the novel application of the scanning tunneling microscope to find and probe the electronic transport properties of single semiconductor nanostructures at temperatures from room temperature to as low as 1.5 K. The current‐voltage characteristics of InGaAs/InAlAs resonant tunneling nanostructures clearly show negative differential resistance. From the dependence of the current on cross‐sectional area the lateral depletion is estimated to be 300 A.
11 CitationsSource
#1R. J. Spah (Bell Labs)H-Index: 1
#2H. F. Hess (Bell Labs)H-Index: 6
Last.K. T. Short (Bell Labs)H-Index: 26
view all 5 authors...
Superconducting thin films of Dy‐Ba‐Cu‐O have been grown on 3 in. sapphire wafers with a molecular beam deposition process. Dissociated oxygen from a glow discharge source was used to improve the oxygen incorporation. This allows growth on a relatively low‐temperature substrate kept below 600 °C followed by an in situ anneal below 400 °C. Thin films of Dy‐Ba‐Cu‐O which were fully superconducting at 40 K have been fabricated by this in situ growth process.
62 CitationsSource
1