Chinese Scientists Invent Molecular Hard Drive With Multi-Level Recording

A group of Chinese scientists published an article in the journal Nature titled “Molecular logic of hard drives for encrypted storage of large amounts of data.” The researchers demonstrated the ability to record up to 96 states in each “point” of the drive, which can be compared to the technology of a six-bit 3D NAND cell. This could be a breakthrough in the creation of high-capacity drives of the future.

Image source: Nature 2025

The achievement was experimentally confirmed using an atomic force microscope. The tip of the microscope measured the surface relief of the “molecular hard disk” and the charge level at each recording point.

The experimental block of the prospective storage device consisted of approximately 200 metal-organic complex molecules (OCM), which during processing self-assembled into a monolayer on the substrate surface. Reading and writing were performed using the tip of a conductive atomic force microscope (C-AFM) with a range of 25 nm.

Digital information was recorded by changing the physicochemical states of molecules (using oxidation-reduction reactions), which manifested itself in the accumulation of a certain number of ions at the recording point. During reading, the current flowing through the material and the tip of the microscope was measured. The more ions were accumulated during the recording process, the higher the current was during reading. In the experiment, its value varied from picoamperes to microamperes.

In addition, a mirror was mounted on the top of the tip, onto which a laser beam was directed. As the nanorelief changed, the tip of the microscope moved, causing the reflected signal to fluctuate. This signal was received by a photodetector, recording the change in the height of the coating, which can also be used to encode information on a molecular hard disk.

Due to the increased bit depth of data storage at each recording point, the total volume of the molecular hard disk can be reduced by 16.7% compared to traditional HDDs with the same data volume. In the future, it is possible to achieve an even greater number of conductivity states, which will increase the bit depth of each recording point and increase the storage density.

The authors also consider the possibility of creating a new floppy disk format: “In the future, through a combination of clever molecular design, synthesis strategy, separate assembly of individual molecules, and the use of flexible substrates, molecular hard disks may even become floppy disks for portable digital devices with high recording density and increased security.”

However, it should be noted that the service life of atomic force microscope tips is still limited, which does not allow us to talk about the imminent commercialization of molecular HDDs. With continuous scanning of the surface, the microscope tip wears out within 5-50 hours, which remains a serious technical obstacle.