Microsoft and Copenhagen University researchers create a new kind of quantum device
+ Microsoft’s Quantum program has made a big bet that new methods for the design, fabrication, and measurement of these types of novel heterostructures will be essential if we are to build a commercial-scale quantum computer. While some might argue that tools invented for classical devices will be sufficient to produce quantum devices, Microsoft and Copenhagen University have already shown in previous work that long-envisioned, but never previously realized, combinations of superconducting and semiconducting elements could be grown and fabricated via MBE and probed by quantum transport, overturning conventional wisdom about what is possible.
Thus, this work, has intrinsic interest as a new device type with a unique mix of features and is also a significant step towards the creation of simpler topological quantum computing systems. It is also another example of how Microsoft and its partners, such as Copenhagen University, are reinventing the science and engineering of quantum devices.
+ The device described in the new Microsoft-Copenhagen University paper is a heterostructure between a semiconductor, a superconductor, and a ferromagnet. The three materials and the interfaces between them were fabricated within an ultra-high-vacuum molecular beam epitaxy (MBE) machine, made possible by the compatibility between the growth and fabrication conditions for the three materials—europium sulfide (ferromagnet), aluminum (superconductor), and indium arsenide (semiconductor)—leading to extremely flat and clean interfaces.
+ [T]he device has gate-tunable superconductivity and ferromagnetism induced in and coexisting in the semiconductor. These two phenomena, ordinarily antithetical, are able to peacefully coexist due to a property of indium arsenide called spin-orbit coupling. In fact, when such coexistence occurs in a quantum wire device of the type fabricated and measured by the Microsoft-Copenhagen University team, Majorana zero modes can result, enabling such a wire to be an integral component of a topological quantum computer.
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