Silicon carbide lattice defects can become qubits

According to the report of the American Physicists Organization Network on November 3 (Beijing time), recently, a physicist from the University of California, Santa Barbara, discovered that the lattice defects contained in silicon carbide can be manipulated as a kind of material at the level of quantum mechanics. The use of qubits at room temperature has made silicon carbide a promising core for next-generation information technology. It is widely used in the electronics industry to explore quantum physics such as ultrafast computing and nanosensing. The related papers were published in the magazine "Nature" published this week.

In traditional semiconductor electronic devices, lattice defects are a kind of flaws, which will "sink" the electrons at a particular crystal lattice position. However, the research team found that in silicon carbide, electrons “collapsed” by lattice defects can initialize their quantum states in some way, and can be accurately manipulated and measured by a combination of light and microwave radiation. . This means that each lattice defect meets the requirements of qubits and is used as a quantum-mechanical analog transistor.

"We look forward to making these imperfect defects perfect and practical, instead of making crystals perfect and orderly. We will use these defects as the foundation of future quantum technology." author of the paper, director of the school's spintronics and quantum computing center, Professor of physics David? Oscar Lom said that most of the material's lattice defects do not have this property, which is closely related to the atomic structure of the material and the electronic characteristics of the semiconductor. The only known system with the same characteristics is the nitrogen-vacancy center in diamonds, which is replaced by nitrogen atoms and adjacent lattice vacancies, and can also be used as a qubit at room temperature. The quantum states of other substances require close to absolute zero. However, diamonds in the center of the nitrogen lattice vacancies are difficult to grow, making it difficult to manufacture integrated circuits.

In contrast, the high-quality silicon carbide crystals used in commerce can be up to several inches in diameter and can be easily used in a variety of electronic, optoelectronic and electromechanical devices. The researchers pointed out that silicon carbide lattice defects are suitable for infrared light, and their energy is very close to that of the light used in modern telecommunication networks. Future integrated quantum devices have sophisticated electronic and optical circuitry. These unique properties make silicon carbide the most attractive candidate.

“Our dream is to be able to freely design quantum machinery equipment. Just as city engineers can design bridges according to their load capacity and span, it is hoped that one day quantum engineers can design quantum electrical equipment according to specifications such as quantum entanglement and interaction with the environment. The author of the paper, author of the Oscar Brom graduate student William? Kyle said.

The editorial circumstance is compared with his own "alternative" relative. The qubit is like the semi-dead "Schrodinger", with a superposition of "this and the other". This difference also signifies the fundamental difference between the computational and computational capabilities of quantum computers and traditional computers. However, if quantum technology is to be used in a truly wide range of applications, it must also change its stringent requirements on the environment and other objective factors. The change from “close to absolute zero” to “room temperature” is undoubtedly one of the important advances. This progress from the lattice defects also tells us once again that if we look at people from different perspectives, there will often be unexpected gains.