Transistor saves 4 bits and bridges with quantum computing

Transistor that stores 4 bits

Engineers at the University of Texas, USA, have created a multivalued transistor, that is, a transistor that can hold more values ​​than the traditional 0 and 1.

With the difficulty of further miniaturizing transistors - the latest 10-nanometer transistors are only 30 atoms wide - the industry has shown increasing interest in so-called multivalued logic , or multi- bit logic, where each component can hold various values .

Another advantage of expanding binary language is that with each transistor encoding more information, the path to neuromorphic computation materializes , which works by mimicking the human brain. Efforts in this direction have so far focused on another family of emerging electronic components, the memoristores .

But Lynn Lee and her colleagues were able to fabricate the traditional electronic component suitable for implementing plurivalent logic, a feat that has been pursued for decades by various university and business teams.

"The concept of multi-value logic transistors is not new, and there have been many attempts to manufacture these components. We have succeeded," said Professor Kyeongjae Cho, the team's coordinator.

Multivalued Transistor

The multivalued, or multi-valent, transistor has as main components two forms of zinc oxide, combined to form a composite nanowire, which is then incorporated together with layers of other materials to form a super-grid. A superrede is a structure formed by different elements, as opposed to the atomic network of a crystal, formed by a single element - a gold diamond is an example of superrede.

While conventional transistors work with a switch - a transistor is on or off, which translates into 0s and 1s of binary language - the multivalued transistor can store two other intermediate signals.

This is possible because zinc oxide is a phase change material, which means that it can take on at least two atomic structures: crystalline or amorphous. Considering these two structures in the two forms of zinc oxide used, plus the on / off, it is possible to save up to four bits.

But the team does not consider the work to be finished: "Zinc oxide is a well-known material that tends to form crystalline solids and amorphous solids, so it was an obvious choice to start with, but it may not be the best material. step will be to analyze how this behavior is universal among other materials, while we try to optimize the technology, "Cho said.

Bridge between electronic computers and quantum computers

The effort is well worth it because, in addition to solving the challenge of miniaturizing transistors and being compatible with today's technology, multivalued logic bridges current electronic computers with future quantum computers , where qubits can hold continuous values .

"The transistor is a very mature technology and quantum computers are far from being marketed. There is a huge gap," said the researcher. "So how do we move from one to the other? We need some kind of evolutionary path, a bridge technology between binary degrees and infinite degrees of freedom." Our work is still based on the current technology of electronic components, so it's not so revolutionary in quantum computing, but it is evolving in that direction. "

Cho adds that after finding a more efficient material than zinc oxide, the next natural step will be to interconnect multivalued transistors with a quantum processor.

Bibliography: ZnO composite nanolayer with mobility edge quantization for multi-value logic transistors Lynn Lee, Jeongwoon Hwang, Jin Won Jung, Jongchan Kim, Ho-In Lee, Sunwoo Heo, Minho Yoon, Sungju Choi, Nguyen Van Long, Jinseon Park, Jae Won Jeong, Jiyoung Kim, Kyung Rok Kim, Dae Hwan Kim, Seongil Im, Byoung Hun Lee, Kyeongjae Cho, Myung Mo Sung Nature Communications Vol. 10, Article number: 1998 DOI: 10.1038 / s41467-019-09998-x