NANOMETER-SCALE RECORDING AND ERASING WITH THE SCANNING TUNNELING MICROSCOPE

DATA storage on magnetic and optical disks and in semiconducting devices is being achieved at ever higher areal densities1,2. The use of the scanning tunnelling microscope (STM) for both data storage and nanofabrication has been explored recently3-9. These approaches use the STM tip to produce nanometre-scale marks or structures on a surface, sometimes with atomic precision. Most studies have, however, neglected erasure of recorded marks (an exception is described in ref. 10), despite the fact that erasure is essential for any practical recording device. Here we demonstrate the use of the STM for reproducible and reversible recording and erasing of marks about 10 nm in size. These are written at ambient temperature and pressure onto the surface of a composite medium consisting of a thin layer of a vanadate glass deposited on vanadium bronze, beta-NaxV2O5. The present recording speed of 1 ms is several orders of magnitude too slow for practical applications; this remains a challenge for future study.