Indexed by: Journal paper

First Author: 王校杰

Correspondence Author: TONG HAO

Co-author: 缪向水,钱航,周凌珺

Journal: Applied Physics Letters

Affiliation of Author(s): 华中科技大学

Discipline: Engineering

First-Level Discipline: Electronic Science And Technology

Document Type: J

Volume: 113

Issue: 23

Page Number: 232903

Key Words: First-principle calculations, Phase transitions, Ferroelectric devices, Ferroelectric materials, Raman spectroscopy, Semiconductor materials, Thin films, Chalcogenides, Depolarization

DOI number: 10.1063/1.5049888

Date of Publication: 4343-12-01

Abstract: A stable ferroelectric phase or Curie temperature (Tc) above room temperature is essential forferroelectric devices. However, the fast Tcdrop of ferroelectric thin films has become a vital factorinhibiting the scaling down of ferroelectric devices. Many efforts have been made to slow downthe Tcdrop in conventional insulating ferroelectric thin films, but they are costly and complex. Asemiconducting ferroelectric, GeTe, is proposed in this letter, which shows an abnormal stability ofthe ferroelectric phase as the film thickness decreases to as thin as 3 nm. The ferroelectric Curietemperatures of GeTe thin films with different thicknesses have been studied using variable-temperature Raman measurements. The self-screening process of free carriers provided by intrinsicGe vacancies in GeTe films plays an important role in cancelling the depolarization field accordingto first principles calculations and results in an abnormal stability of ferroelectricity in ultrathinGeTe films. Self-screening by free carriers in GeTe unravels that the ferroelectric phase couldremain stable in low dimension semiconducting ferroelectrics. These results provide a straightfor-ward solution for high density ferroelectric devices and show promising application of semiconducting ferroelectrics in large current ferroelectric diodes.

Links to published journals: https://pubs.aip.org/aip/apl/article/113/23/232903/36366/Self-screening-induced-abnormal-stability-of