A kilobyte rewritable atomic memory

The ability to manipulate individual atoms by means of scanning tunneling microscopy (STM) opens op opportunities for storage of digital data on the atomic scale. Recent achievements in this direction include data storage based on bits encoded in the charge state (1), the magnetic state (2), or the local presence (3) of single atoms or atomic assemblies. However, a key challenge at this stage is the extension of such technologies into large-scale rewritable bit arrays. We demonstrate a digital atomic-scale memory of up to 1 kilobyte (8000 bits) using an array of individual surface vacancies in a chlorine terminated Cu(100) surface (4). The chlorine vacancies are found to be stable at temperatures up to 77 K. The memory, crafted using scanning tunneling microscopy at low temperature, can be read and re-written automatically by means of atomic-scale markers, and offers an areal density of 502 Terabits per square inch, outperforming state-of-the-art hard disk drives by three orders of magnitude. 1. J. Repp et al., Science 305, 493--5 (2004) 2. S. Loth et al., Science 335, 196--9 (2012) 3. R. Bennewitz et al., Nanotechnology 13, 499 (2002) 4. F. E. Kalff et al., Nature Nanotechnology 11, 926--9 (2016)