Ivar Giaever

Ivar Giaever is a Norwegian-American physicist who shared the 1973 Nobel Prize in Physics for experimental discoveries concerning tunneling phenomena in superconductors.

Quantum tunneling: A quantum process in which a particle crosses a barrier that classical physics says it cannot cross. Electron tunneling through thin insulating barriers made Giaever’s superconductivity experiments possible.
Metal–insulator–metal junction: A structure of two metal electrodes separated by a thin insulating layer that permits electron tunneling. Giaever used thin-film junctions of this kind to measure tunneling across a superconductor’s energy gap.
Nobel Prize in Physics: An annual international award recognizing major contributions to physics. Giaever shared its 1973 prize for experimental discoveries concerning tunneling phenomena in superconductors.
Scanning tunneling microscope: An instrument that maps surfaces by measuring tunneling current between a sharp tip and a sample. It extends tunneling-current measurements into spatially resolved imaging of material surfaces.
Superconductivity: A state of matter with zero electrical resistance and magnetic-field expulsion below a critical temperature. Giaever measured how superconducting energy gaps shape tunneling currents.
Current–voltage characteristic: A curve showing how electrical current through a device varies with applied voltage. Its changes at the gap threshold provided the experimental signature of superconducting tunneling.
Leo Esaki: A Japanese physicist awarded the 1973 Nobel Prize in Physics for discovering electron tunneling in semiconductors. Esaki shared the 1973 prize with Giaever for a related tunneling discovery in a different material system.
Superconducting gap spectroscopy: Measurement of a superconductor’s energy gap through its electronic spectrum. Giaever’s junction method became a direct way to extract superconducting gap values.
Energy gap: A range of energies unavailable to excitations in a material or physical system. The superconducting energy gap appeared as a threshold in Giaever’s measured current-voltage curves.
Density of states: The number of available quantum states per energy interval in a physical system. Tunneling current reflects the available electronic states, including the gap Giaever resolved.

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