Thermodynamic Constraints in Dynamic Random-Access Memory Cells: Experimental Verification of Energy Efficiency Limits in Information Erasure

TL;DR

This study experimentally investigates the energy efficiency of silicon DRAM cells during information erasure, revealing thermodynamic constraints that prevent reaching the Landauer limit and highlighting fundamental limits in electronic memory operations.

Contribution

The paper experimentally demonstrates thermodynamic constraints in DRAM cells that hinder achieving the Landauer limit, providing new insights into energy limits in electronic memory devices.

Findings

Efficiency decreases as erasure error probability decreases.

Landauer limit is not achieved even with effectively infinite-time erasure.

Thermodynamic constraints prevent initial state preparation in thermal equilibrium.

Abstract

We measured the energy efficiency of information erasure using silicon DRAM cells capable of counting charges on capacitors at the single-electron level. Our measurements revealed that the efficiency decreased as the erasure error probability decreased, and notably, the Landauer limit was not achieved even under effectively infinite-time bit erasure. By comparing the measured efficiency with the Landauer limit, we identified a thermodynamic constraint that prevents DRAM from reaching this limit: the inability to prepare the initial state in thermal equilibrium, which in turn prohibits quasistatic operations. This finding has broad implications for DRAM cells and for many electronic circuits sharing similar structures. Furthermore, it validates our experimental approach to discovering thermodynamic constraints that impose tighter, practically relevant limits, opening a new direction in information thermodynamics research.