Comment on ``Elastic Stabilization of a Single-Domain Ferroelectric State in Nanoscale Capacitors and Tunnel Junctions" [N.A. Pertsev and H. Kohlstedt, Phys. Rev. Lett. 98, 257603 (2007).]

TL;DR

This paper critically examines a previous study claiming nanoscale capacitors can maintain out-of-plane polarization for memory use, arguing that the original conclusions are not supported by their calculations and should be reversed.

Contribution

The authors provide a straightforward critique showing that the earlier claims about polarization stability in nanoscale ferroelectric devices are not justified.

Findings

Original claims about polarization stability are unsupported

Calculations suggest polarization may not be stable at nanoscale

Reversal of the original conclusion is warranted

Abstract

In a recent Letter [N.A. Pertsev and H. Kohlstedt, Phys. Rev. Lett. 98, 257603 (2007)] the authors claim that "even nanoscale capacitors and tunnel junctions may have out of plane polarization sufficient for memory applications." Here we show in an elementary way that this conclusion is not substantiated by their calculations and that they should have come to the opposite conclusion within their approximations.