Using Diamond For Quantum Computing
Contrary to normal computers using bits (0 & 1), quantum computers use “qubits”. Qubits can exist in multiple states simultaneously thanks to two quantum properties: superposition and entanglement.
- Superposition allows qubits to represent both 0 and 1 at the same time, exponentially increasing the data that can be processed compared to classical bits.
- Entanglement links qubits in such a way that the state of one qubit can instantaneously affect another, even across great distances.
These properties enable QPUs to solve highly complex problems much faster than classical computers by exploring multiple solutions simultaneously.
“The advantage of qubits is that they can hold much more information than regular bits can. This means that they can also give us much more information about their environment, making them extremely valuable as sensors, for example.”
Alastair Stacey- Managing principal research physicist and head of quantum materials and devices at PPPL.
However, qubits are extremely fragile, and measuring their properties is not an easy task.
So what if we instead counted on one of the hardest materials on earth – diamond – to perform tasks in our most advanced computer? This is the vision of researchers at Princeton University, who published recently in Diamond And Related Materials, under the title “Quantum chemistry model of surface reactions and kinetic model of diamond growth: Effects of CH3 radicals and C2H2 molecules at low-temperatures CVD”.
This joins the works of other researchers at the University of Melbourne and Princeton University, published under the title “Methods for Color Center Preserving Hydrogen-Termination of Diamond.”
Growing Diamonds On Demand
Diamonds, historically only a natural stone, are mostly manufactured from raw carbon these days. However, this process requires very intense heat and pressure, so it cannot be combined with other materials like silicon used in computer chips. For this, low-temperature diamond manufacturing is needed.
Some methods have already been explored, like using acetylene and a technique called “plasma-enhanced chemical vapor deposition”.
Source: PPPL
The problem with it is that while it can grow microscopic diamonds, it also deposits a lot of soot, which can grow on top of the diamond and inhibit performance for optics, sensors, and chips. Until now it was not clear why the soot formed instead of diamonds.
Goldilocks Temperature & Hydrogen
The researchers found that there is a precise temperature at which the process creates a diamond. Above this critical temperature, acetylene contributes mostly to diamond growth. Below this critical temperature, it contributes mostly to soot growth.
Source: Diamond And Related Materials
Another factor is the activity of hydrogen atoms near the surface of the diamond. With more hydrogen near the surface, more diamonds can form, even at lower temperatures.
“Hydrogen atoms don’t fuel diamond growth directly, but hydrogen dissociation, or breakdown, is crucial for transforming methane into acetylene and transporting atomic hydrogen to the diamond growth surface. These are both important for diamond growth,”
Alexander Khrabry – Princeton University Research Scholar
Together, these insights in diamond formation open the way for reliably creating microscopic diamonds directly inside silicon semiconductors without damaging the rest of the material with high temperatures or creating unwanted soot.
Quantum Diamonds
Simple diamonds made only on carbons could have some applications in optics and sensors. But more advanced forms of diamonds could be even more useful.
For example, quantum diamonds are made when some of the carbon atoms forming the diamond are replaced by other atoms, like for example nitrogen, and some other carbon atoms are just removed. This creates a so-called nitrogen-vacancy (NV).
In such a diamond, the electrons inside start to follow quantum rules instead of classic physics, which could be used to build qubits.
“The electrons in this material don’t behave according to the laws of classical physics as heavier particles do. Instead, like all electrons, they behave according to the laws of quantum physics.”
Alastair Stacey- Managing principal research physicist and head of quantum materials and devices at PPPL.
Perfecting The Diamond Cookbook
Until now, the method of using plasma to create diamonds has been far from precise. It was using a lot of trial and error, as the theory of what exactly happens at the surface of the diamond is not well understood.
Ideally, plasma could also be used to add a mono-atomic layer of hydrogen on top of the diamond. But in the case of quantum diamonds, the high temperature would destroy the nitrogen-vacancy.
So the researchers built an elaborate analytical system (using photoluminescence spectroscopy) to judge what works best for creating a hydrogen layer on NV diamonds.
Source: Advanced Materials Interface
They found that 2 new methods could be used, although each with its own drawbacks for now.
Source: Advanced Materials Interface
- Forming gas annealing, which uses a mixture of hydrogen molecules and nitrogen gas, worked but required very pure hydrogen gas without any oxygen, something difficult to achieve at low temperatures.
- Cold plasma termination, which uses hydrogen plasma indirectly, did not damage the NV center and was easier to implement, but created a lower quality of hydrogen layer on the diamond.
“This highlights the trade-off between surface quality and NV properties that will have to be balanced in future applications. For instance, in biomolecular sensing projects, it is absolutely crucial that NVs be preserved close to surfaces.”
Daniel McCloskey – Researcher at the University of Melbourne.
Overall, these discoveries open the way to a few new, previously hard or impossible applications for diamonds:
- Direct production onto silicon semiconductors, integrating diamonds directly into circuits, sensors, and transistors.
- Production of quantum diamonds into functional qubits, including a finely tuned hydrogen layer on the surface of the diamond.
New Quantum Computers
Quantum computers have so far been built out of known methods stemming from the traditional manufacturing tactics used by the semiconductor industry. But with quantum technology so different from normal computing, it makes sense that new materials are likely a better fit than traditional silicon.
This can include diamonds, for one day allowing quantum computing to be performed at room temperature, something that would not only decrease costs drastically but also help in creating larger quantum computers.
“Making a quantum simulator with more than 50 qubits and a room-temperature quantum computer opens the door to scaling up to a higher number of qubits, like 100 or 1000, which would be a game-changer for areas like cryptography, AI, and materials science.
This capability would allow scientists to discover life-saving drugs faster, solve hard optimization problems, or develop energy-saving technologies more efficiently.”
Martin Koppenhöfer – Project coordinator at SPINUS
Besides diamonds, other new innovative materials like for example piezoelectric nanomechanical resonators made of aluminum nitride could also be used for quantum sensors or quantum transducers.
Overall, it is likely that advanced new materials will be a solid alternative to silicon and push the promise of quantum computing much further than we could guess today.
Investing In Quantum Computing
Quantum computing is only getting started but has already caught the attention of every large computing firm that has powered the silicon revolution so far.
It might forever be limited to niche applications more than take place in our computers, but it could still become instrumental in the modelization of physics, biology, material sciences, cryptography, and military applications.
You can invest in quantum computing companies through many brokers, and you can find here, on securities.io, our recommendations for the best brokers in the USA, Canada, Australia, the UK, as well as many other countries.
If you are not interested in picking specific companies, you can also look into ETFs like the ProShares Nanotechnology ETF (TINY) or the WisdomTree Cloud Computing Fund (WCLD) which will provide a more diversified exposure to capitalize on quantum computing & nanotech stocks.
Or you can look at our list of the “Top 10 Nanotechnology Stocks” and “5 Best Quantum Computing Companies”.
Quantum Computing Companies
International Business Machines Corporation (IBM +0.04%)
International Business Machines Corporation (IBM) was the leading force behind the commercialization of the first mainframe computer.
However, it has recently fallen behind in the production volume of other tech giants like Apple (AAPL +0.96%), TSMC (TSM -2.1%), and NVIDIA (NVDA -0.84%)
It is, however, at the forefront of the development of quantum computers. For example, it developed its 127-qubit “Eagle” quantum computer, which was followed by a 433-qubit system known as “Osprey.”
And this is now followed by “Condor”, a 1,121 superconducting qubit quantum processor based on cross-resonance gate technology, together with “Heron”, a quantum processor at the very edge of the field.
Quantum computers could benefit from improved magnetic control, enhancing qubit stability and reliability, which are essential for processing power.
Similarly, advancements in superconductors, which rely on controlled magnetic fields, could lead to more efficient energy transmission and cooling systems, particularly at higher temperatures.
IBM is involved in most of the other cutting-edge innovations in computing and the semiconductors industry. These include conducting organic materials, neuromorphic computing, photonics, etc.
To some extent, IBM has become a “patent company” with expertise in developing new computing methods and licensing them to the industry.
So far, it seems very determined to hold as many key patents in all the non-silicon computing methods it can get, replicating its past success when contributing massively to developing the semiconductor industry into the giant it is today.