Can We Break the Landauer Bound in Spin-Based Electronics?

Abstract

We found that the minimum energy of reading or erasing a spin datum should be expressed by $\Delta E=2~\mu _{B}B$ , in contrast to ${\Delta E=k}_{B}T\,\,ln(2)$ proposed by Landauer in 1961. The physics of using a spin’s orientation to represent a bit of information is fundamentally different from that of using a particle’s position in classical charge-based data storage: the former is quantum-dynamic (independent of temperature below the Curie point), whereas the latter is thermodynamic (dependent on temperature). Quantitatively, this new energy bound associated with a new information erasure protocol was estimated as $1.64\times {10}^{-36}J$ , 15 orders of magnitude lower than the Landauer bound ( $3 \times {10}^{-21}J$ ), at no cost of angular momentum and increased total entropy. In this new information erasure protocol, there is no need to move the electron from one side of the potential well to the other side otherwise the energy used to retain the defined spin state still needs to be greater than the existing thermal fluctuation (the Landauer bound). We verified our new energy bound based on a number of experiments including the Rydberg atom and the spin-spin interaction.