  Non-volatile magnetic storage, from 1940s magnetic core to present day
racetrack memory and magnetic anisotropy switching devices rely on the
metastability of magnetic domains to store information. However, the inherent
inefficiency of converting the information-carrying charge current into
magnetization switching sets fundamental limitations in energy consumption.
Other non-magnetic non-volatile memories such as memristors, ferroelectric
memory and phase change memory devices also rely on energetically relatively
costly crystal structural rearrangements to store information. In contrast,
conventional electronic charge states in quantum dots for example, can be
switched in femtoseconds with high efficiency, but any stored information
dissipates rapidly. Here we present a radically different approach in the form
of a charge-configuration memory (CCM) device that relies on
charge-injection-driven electronic crystal melting and topological protection
of the resulting electronic domain configurations of a two-dimensional
electronic crystal to store information. With multiprobe scanning tunneling
microscopy (STM) we show microscopically, within an operational device, how
dislocations in the domain ordering lead to metastability by a mechanism that
is topologically equivalent to magnetic bubble memory. The devices have a very
small switching energy (<2.2 fJ/bit), ultrafast switching speed of <11 ps and
operational range over more than 3 orders of magnitude in temperature (<250 mK
~ 190 K). Together with their simple functionality, a large resistance
switching ratio, straightforward fabrication and impressive endurance, CCM
devices introduce a new memory paradigm in emerging cryo-computing and other
high-performance computing applications that require ultrahigh speed and low
energy consumption.
