Ferroelectric switched all-metallic-oxide $p$-$n$ junctions

TL;DR

This paper demonstrates the creation of ferroelectric switched all-metallic-oxide $p$-$n$ junctions with high rectification, low reversed current, and large breakdown voltage, using ferroelectric polarization to control metallic oxide interfaces.

Contribution

It introduces the first all-metallic-oxide ferroelectric $p$-$n$ junctions that are switched by combined built-in and ferroelectric reversed polarized fields, differing from traditional semiconductor junctions.

Findings

Achieved negligible reversed current of 10^{-9} A.

Demonstrated large breakdown voltage over 7 V.

Observed ultrahigh rectification ratio exceeding 2×10^4.

Abstract

We report the first formation of the metallic $p$-$n$ junctions, the ferroelectric (Ba,Sr)TiO$_3$ (BST) switched optimally electron-doped ($n$-type) metallic T'-phase superconductor, (La,Ce)$_2$CuO$_4$ (LCCO), and hole-doped ($p$-type) metallic CMR manganite (La,Sr)MnO$_3$ (LSMO) junctions. In contrast with the previous semiconductor $p$-$n$ ($p$-$I$-$n$) junctions which are switched by the built-in field $V_0$, the present metallic oxides $p$-$I$-$n$ junctions are switched by double barrier fields, the built-in field $V_0$, and the ferroelectric reversed polarized field $V_{rp}$, both take together to lead the junctions to possess definite parameters, such as definite negligible reversed current ($10^{-9}$ A), large breakdown voltage ($>$7 V), and ultrahigh rectification ($>2\times10^4$) in the bias voltage 1.2 V to 2.0 V and temperature range from 5 to over 300 K. The related transport feature, barrier size effect, and temperature effect are also observed and defined.