To make it possible to control an electromagnetic field environment which influences the characteristic of a minute tunnel junction greatly, by uniting the minute tunnel junction with a two-dimensional electron gas in first and second heteroconstruction semiconductors.
A semiconductor heterojunction 51 containing an indium arsenic layer for forming a two-dimensional electron gas is grown by a molecular beam epitaxy method on an insulating substrate 55 made out of indium phosphorus, and layers being more above than an InAs layer are removed by etching, and a metal-two-dimensional electron gas contact part 56 is formed. A minute tunnel junction-two-dimensional electron gas (2DEG) contact part is for bringing a minute tunnel junction into contact with a 2DEG. It becomes possible to remove excessive quasiparticles from a junction electrode, by putting a normal metal region made out of 2DEG in the vicinity of the minute tunnel junction. As a result of this, it becomes possible to realize a thermally balanced state where the behavior of pairs of coopers in a superconducting state is determined by the band of a base condition.
TANAKA HIROTAKA
TAKAYANAGI HIDEAKI
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