Towards zero-power ICT

Abstract

Is it possible to operate a computing device with zero energy expenditure? This question, once considered just an academic dilemma, has recently become strategic for the future of information and communication technology. In fact, in the last forty years the semiconductor industry has been driven by its ability to scale down the size of the complementary metal-oxide semiconductor-field-effect transistor, the building block of present computing devices, and to increase computing capability density up to a point where the power dissipated in heat during computation has become a serious limitation. To overcome such a limitation, since 2004 the Nanoelectronics Research Initiative has launched a grand challenge to address the fundamental limits of the physics of switches. In Europe, the European Commission has recently funded a set of projects with the aim of minimizing the energy consumption of computing. In this article we briefly review state-of-the-art zero-power computing, with special attention paid to the aspects of energy dissipation at the micro- and nanoscales.

Quantum Landauer erasure with a molecular nanomagnet

“…The performance of our spin register in terms of energy-time cost is orders of magnitude better than existing memory devices to date. The result shows that thermodynamics sets a limit on the energy cost of certain quantum operations and illustrates a way to enhance classical computations by using a quantum system.While a computation performed with an ideal binary logic gate (for example, NOT) has no lower energy dissipation limit [5][6][7] , one carried out in a memory device does. The reason is that in the former the bit is merely displaced isentropically in the space of states, whereas in the latter the minimal operation, called Landauer erasure, entails resetting the memory irrespective of its initial state.…”

“…While a computation performed with an ideal binary logic gate (for example, NOT) has no lower energy dissipation limit [5][6][7] , one carried out in a memory device does. The reason is that in the former the bit is merely displaced isentropically in the space of states, whereas in the latter the minimal operation, called Landauer erasure, entails resetting the memory irrespective of its initial state.…”

Minimum Energy of Computing, Fundamental Considerations

“…A typical work function of stable metals is 4-5 eV. In realistic cases the barrier walls have finite slope and rounded corners due to the image force effect [19,20]. For smaller gaps, for example when the left-hand electrode is moving towards the right-hand electrode under external field, the shape of the barrier changes, with barrier height reducing and more prominent corner rounding (Fig.…”

Micromagnetic study of minimum-energy dissipation during Landauer erasure of either isolated or coupled nanomagnetic switches

“…In contrast, nanomagnetic logic (NML) devices based on clusters of interacting magnetic dots, are intrinsically nonvolatile and require very low operation power since logic operations are performed without the flow of any electrical current and the unavoidable heat dissipation. However, the Landauer principle [2] and related works on the thermodynamical aspects of computation [3][4][5][6][7] define a fundamental limit to the minimum energy required for a single-bit erasure (or restore to 1) operation. The value of this minimum energy is k B T × ln (2) and it is known as the Landauer limit [2].…”