In the James Bond song Diamonds Are Forever, Shirley Bassey sings the praises of the longevity of diamonds. She admires how these precious gems “lustre on” after love ends. If, as Bassey observes, diamonds are forever, then data could be too. Recent research shows that diamonds can be used as memory platforms for long-term, dense data storage.
Like diamonds, data storage itself is a precious, but finite, resource. There simply is not enough space for the incessant increase of information. The world is drowning in what The Economist describes as a data deluge. According to The Economist, “everywhere you look, the quantity of information in the world is soaring. Merely keeping up with this flood, and storing the bits that might be useful, is difficult”.
This difficulty presents a serious challenge to current available technologies that manage, use, and store data. For instance, the storage densities of common digital storage mediums, such as hard disk drives, flash drives, CDs, DVDs or Blu-ray discs, are quite low for contemporary and future storage needs. These technologies, in other words, are reaching their limits insofar as long-term data storage is concerned.
There is consequently a desperate need for more and new kinds of data storage. This desperate need is motivating novel research into data storage, exploring the pressing question of how to create and ensure accessible, durable, secure, and long-term storage capabilities for the ever-growing amounts and kinds of information.
Researchers at the City College of New York recently demonstrated the data storage possibilities presented by one of the earth’s hardest naturally occurring substances: diamonds. Presently, data encoded in a tiny diamond, about half as long as rice grain, could last for an indefinite period of time while storing a hundred times more information than a single DVD. Encoding all of a DVD’s information into a diamond would only take up about one per cent of its space. Even that big amount of data storage is still not that much within the context of the rising data deluge; however, it has the possibility of expanding to the equivalent of one million DVDs and maybe more.
The perfect diamonds for data storage are not the apparently perfect and pure gems found in the luxury shops of Harry Winston. Defects and impurities in the gems are necessary. The City College of New York researchers, in fact, are exploring the essential role played by defects in diamonds for data storage. The lead researchers, Siddarth Dhomkar and Jacob Henshaw, describe that they are “experimenting with a perhaps unexpected memory material you may even be wearing on your ring finger now: diamond. On the atomic level, these crystals are extremely orderly – but sometimes defects arise. We’re exploiting these defects as a possible way to store information in three dimensions”.
It is currently a complex process to place and store data in diamonds. Put simply, diamonds are crystalline structures comprised of well-ordered arrays of carbon atoms. Sometimes there is a fracture in the order where a carbon atom is missing that results in a vacancy. Sometimes, further still, a nitrogen atom may take the place of a carbon atom. When a vacancy occurs next to a rogue nitrogen atom, the composite defect is called a nitrogen vacancy centre. These nitrogen vacancy centres make these gems ideal memory platforms because they offer empty spaces in which data can be stored.
According to Dhomkar and Henshaw, the lead researchers, the nitrogen vacancy centres can be considered as nanoscopic bits. The process of encoding, writing, and reading data is complex, but, simply put, it is based on a binary system using only two digits – one and zero – to represent information. They explain that “if the defect has an extra electron, the bit is one. If it doesn’t have an extra electron, the bit is zero. This electron yes/no, on/off, one/zero property opens the door for turning the NV centre’s charge state into the basis for using diamonds as a long-term storage medium.”
The researchers therefore use these nitrogen vacancy centres as substitutes for the binary ones and zeros: if the vacancy has an electron, it is a one; if it is empty, it is a zero. The nitrogen vacancy centres, in other words, can trap an electron and also be forced to release it, thereby permitting a nitrogen vacancy centre with or without an electron to be treated as a binary one or zero.
Researchers, using lasers, can selectively change the charge state of a nitrogen vacancy centre to inject or eject electrons. A green laser can inject and trap an electron in the defect, a high-power red laser can eject an electron from it, and a low-power red laser can determine if an electron is trapped or not. The researchers therefore encode and read the data like a computer reads ones and zeros; however, instead of digits, light is used to indicate the presence or absence of electrons.
Further, unlike DVDs or hard drives, the diamond can be written and rewritten onto countless times without degrading the material. If the diamond is in total darkness, moreover, the defects maintain their charged or discharged states, meaning that their memory state could, according to Dhomkar and Henshaw, persist “virtually forever”. The defects in diamonds do not change; consequently, the encoded data could last as long as the diamonds themselves.
This increased data storage space, and infinite rewrite capabilities, offered by diamonds are further enhanced by 3-D possibilities. Unlike a typical DVD a diamond has multiple layers into which the data could be placed. While a typical DVD, in other words, provides a 2-D plane, a diamond provides a 3-D model.
This research shows that the amount of space in a single tiny diamond far surpasses most contemporary data storage capabilities in terms of space, write and rewrite abilities, 3-D features, and longevity. But this research is in its infancy. There is much work to be done before information technology departments start installing and consumers begin purchasing diamond drives. But these early results point to promising new directions for the future of new and more kinds of data storage.
James Bond should enlist Shirley Bassey to sing that data in diamonds are forever.
■ Marc Kosciejew is a lecturer and former head of department of library, information, and archive sciences.