Abstract
Strontium titanate (SrTiO 3 ) is the "silicon" in the emerging field of oxide electronics. While bulk properties of this material have been studied for decades, new unexpected phenomena have recently been discovered at the nanoscale, when SrTiO 3 forms an ultrathin film or an atomically sharp interface with other materials. One of the striking discoveries is room-temperature ferroelectricity in strain-free ultrathin films of SrTiO 3 driven by the Ti Sr antisite defects, which generate a local dipole moment polarizing the surrounding nanoregion. Here, we demonstrate that these polar defects are not only responsible for ferroelectricity, but also propel the appearance of highly conductive channels, "hot spots", in the ultrathin SrTiO 3 films. Using a combination of scanning probe microscopy experimental studies and theoretical modeling, we show that the hot spots emerge due to resonant tunneling through localized electronic states created by the polar defects and that the tunneling conductance of the hot spots is controlled by ferroelectric polarization. Our finding of the polarization-controlled defect-assisted tunneling reveals a new mechanism of resistive switching in oxide heterostructures and may have technological implications for ferroelectric tunnel junctions. It is also shown that the conductivity of the hot spots can be modulated by mechanical stress, opening a possibility for development of conceptually new electronic devices with mechanically tunable resistive states.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 491-497 |
| Number of pages | 7 |
| Journal | Nano letters |
| Volume | 18 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 10 2018 |
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All Science Journal Classification (ASJC) codes
- Bioengineering
- Chemistry(all)
- Materials Science(all)
- Condensed Matter Physics
- Mechanical Engineering
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Tunneling Hot Spots in Ferroelectric SrTiO 3 . / Lu, Haidong; Lee, Daesu; Klyukin, Konstantin; Tao, Lingling; Wang, Bo; Lee, Hyungwoo; Lee, Jungwoo; Paudel, Tula R.; Chen, Long-qing; Tsymbal, Evgeny Y.; Alexandrov, Vitaly; Eom, Chang Beom; Gruverman, Alexei.
In: Nano letters, Vol. 18, No. 1, 10.01.2018, p. 491-497.Research output: Contribution to journal › Article
TY - JOUR
T1 - Tunneling Hot Spots in Ferroelectric SrTiO 3
AU - Lu, Haidong
AU - Lee, Daesu
AU - Klyukin, Konstantin
AU - Tao, Lingling
AU - Wang, Bo
AU - Lee, Hyungwoo
AU - Lee, Jungwoo
AU - Paudel, Tula R.
AU - Chen, Long-qing
AU - Tsymbal, Evgeny Y.
AU - Alexandrov, Vitaly
AU - Eom, Chang Beom
AU - Gruverman, Alexei
PY - 2018/1/10
Y1 - 2018/1/10
N2 - Strontium titanate (SrTiO 3 ) is the "silicon" in the emerging field of oxide electronics. While bulk properties of this material have been studied for decades, new unexpected phenomena have recently been discovered at the nanoscale, when SrTiO 3 forms an ultrathin film or an atomically sharp interface with other materials. One of the striking discoveries is room-temperature ferroelectricity in strain-free ultrathin films of SrTiO 3 driven by the Ti Sr antisite defects, which generate a local dipole moment polarizing the surrounding nanoregion. Here, we demonstrate that these polar defects are not only responsible for ferroelectricity, but also propel the appearance of highly conductive channels, "hot spots", in the ultrathin SrTiO 3 films. Using a combination of scanning probe microscopy experimental studies and theoretical modeling, we show that the hot spots emerge due to resonant tunneling through localized electronic states created by the polar defects and that the tunneling conductance of the hot spots is controlled by ferroelectric polarization. Our finding of the polarization-controlled defect-assisted tunneling reveals a new mechanism of resistive switching in oxide heterostructures and may have technological implications for ferroelectric tunnel junctions. It is also shown that the conductivity of the hot spots can be modulated by mechanical stress, opening a possibility for development of conceptually new electronic devices with mechanically tunable resistive states.
AB - Strontium titanate (SrTiO 3 ) is the "silicon" in the emerging field of oxide electronics. While bulk properties of this material have been studied for decades, new unexpected phenomena have recently been discovered at the nanoscale, when SrTiO 3 forms an ultrathin film or an atomically sharp interface with other materials. One of the striking discoveries is room-temperature ferroelectricity in strain-free ultrathin films of SrTiO 3 driven by the Ti Sr antisite defects, which generate a local dipole moment polarizing the surrounding nanoregion. Here, we demonstrate that these polar defects are not only responsible for ferroelectricity, but also propel the appearance of highly conductive channels, "hot spots", in the ultrathin SrTiO 3 films. Using a combination of scanning probe microscopy experimental studies and theoretical modeling, we show that the hot spots emerge due to resonant tunneling through localized electronic states created by the polar defects and that the tunneling conductance of the hot spots is controlled by ferroelectric polarization. Our finding of the polarization-controlled defect-assisted tunneling reveals a new mechanism of resistive switching in oxide heterostructures and may have technological implications for ferroelectric tunnel junctions. It is also shown that the conductivity of the hot spots can be modulated by mechanical stress, opening a possibility for development of conceptually new electronic devices with mechanically tunable resistive states.
UR - http://www.scopus.com/inward/record.url?scp=85040310530&partnerID=8YFLogxK
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U2 - 10.1021/acs.nanolett.7b04444
DO - 10.1021/acs.nanolett.7b04444
M3 - Article
C2 - 29236501
AN - SCOPUS:85040310530
VL - 18
SP - 491
EP - 497
JO - Nano Letters
JF - Nano Letters
SN - 1530-6984
IS - 1
ER -