DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Ferroelectric switching of a two-dimensional metal

Journal Article · · Nature (London)
 [1];  [1];  [1];  [1];  [1];  [2];  [3];  [4];  [1]
  1. Univ. of Washington, Seattle, WA (United States). Dept. of Physics
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Univ. of Tennessee, Knoxville, TN (United States). Dept. of Physics and Astronomy
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division
  4. Univ. of Washington, Seattle, WA (United States). Dept. of Physics. Dept. of Materials Science and Engineering

A ferroelectric is a material with a polar structure whose polarity can be reversed (switched) by applying an electric field. In metals, itinerant electrons screen electrostatic forces between ions, which explains in part why polar metals are very rare. Screening also excludes external electric fields, apparently ruling out the possibility of ferroelectric switching. However, in principle, a thin enough polar metal could be sufficiently penetrated by an electric field to have its polarity switched. In this paper we show that the topological semimetal WTe2 provides an embodiment of this principle. Although monolayer WTe2 is centro-symmetric and thus non-polar, the stacked bulk structure is polar. We find that two- or three-layer WTe2 exhibits spontaneous out-of-plane electric polarization that can be switched using gate electrodes. We directly detect and quantify the polarization using graphene as an electric-field sensor. Moreover, the polarization states can be differentiated by conductivity and the carrier density can be varied to modify the properties. Finally, the temperature at which polarization vanishes is above 350 kelvin, and even when WTe2 is sandwiched between graphene layers it retains its switching capability at room temperature, demonstrating a robustness suitable for applications in combination with other two-dimensional materials.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Washington, Seattle, WA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF) (United States); Air Force Office of Scientific Research (AFOSR) (United States)
Grant/Contract Number:
AC05-00OR22725; SC0002197; SC0018171
OSTI ID:
1462831
Journal Information:
Nature (London), Journal Name: Nature (London) Vol. 560; ISSN 0028-0836
Publisher:
Nature Publishing GroupCopyright Statement
Country of Publication:
United States
Language:
English

References (41)

Crystal Stability and the Theory of Ferroelectricity journal November 1959
Domain Structure and Defects book January 1998
Thin-film ferroelectric materials and their applications journal November 2016
Symmetry Considerations on Martensitic Transformations: "Ferroelectric" Metals? journal February 1965
Observation of the quantum spin Hall effect up to 100 kelvin in a monolayer crystal journal January 2018
Physics of thin-film ferroelectric oxides journal October 2005
‘Ferroelectric’ metals reexamined: fundamental mechanisms and design considerations for new materials journal January 2016
Critical enhancement of thermopower in a chemically tuned polar semimetal MoTe$_{\bf 2}$ text January 2017
Layer-dependent ferromagnetism in a van der Waals crystal down to the monolayer limit journal June 2017
Type-II Weyl semimetals journal November 2015
Edge conduction in monolayer WTe2 text January 2016
Edge conduction in monolayer WTe2 journal April 2017
Type-II Weyl Semimetals text January 2015
Polar metals by geometric design journal April 2016
Quantum spin Hall state in monolayer 1T'-WTe2 journal June 2017
Layer-dependent Ferromagnetism in a van der Waals Crystal down to the Monolayer Limit text January 2017
Discovery of robust in-plane ferroelectricity in atomic-thick SnTe journal July 2016
Experimental observation of the quantum Hall effect and Berry's phase in graphene journal November 2005
Fast pick up technique for high quality heterostructures of bilayer graphene and hexagonal boron nitride text January 2014
Physics of thin-film ferroelectric oxides text January 2005
Magnetoresistance and quantum oscillations of an electrostatically tuned semimetal-to-metal transition in ultrathin WTe 2 journal January 2017
Ferroelectricity and Phase Transitions in Monolayer Group-IV Monochalcogenides journal August 2016
Atomically Thin MoS2 A New Direct-Gap Semiconductor journal September 2010
Crystal stability and the theory of ferroelectricity journal October 1960
Emergence of Ferroelectricity at a Metal-Semiconductor Transition in a 1 T Monolayer of MoS 2 journal April 2014
Examining Graphene Field Effect Sensors for Ferroelectric Thin Film Studies journal August 2013
Large, non-saturating magnetoresistance in WTe2 journal September 2014
Domain wall nanoelectronics journal February 2012
Fast pick up technique for high quality heterostructures of bilayer graphene and hexagonal boron nitride journal July 2014
Experimental Observation of Quantum Hall Effect and Berry's Phase in Graphene text January 2005
Quantum spin Hall effect in two-dimensional transition metal dichalcogenides journal November 2014
A ferroelectric-like structural transition in a metal journal September 2013
Observation of Fermi arcs in the type-II Weyl semimetal candidate WTe 2 journal September 2016
Critical enhancement of thermopower in a chemically tuned polar semimetal MoTe 2 journal November 2016
Two-dimensional gas of massless Dirac fermions in graphene journal November 2005
Two-dimensional ferroelectric films journal February 1998
Room-temperature ferroelectricity in CuInP2S6 ultrathin flakes journal August 2016
`Ferroelectric' Metals Reexamined: Fundamental Mechanisms and Design Considerations for New Materials text January 2015
Boron nitride substrates for high-quality graphene electronics journal August 2010
Applications of Modern Ferroelectrics journal February 2007
A ferroelectric-like structural transition in a metal text January 2015

Cited By (43)

Atomic-scale mapping of interface reconstructions in multiferroic heterostructures journal December 2018
A room-temperature ferroelectric semimetal journal July 2019
Thickness‐Dependent In‐Plane Polarization and Structural Phase Transition in van der Waals Ferroelectric CuInP 2 S 6 journal December 2019
Artificial two-dimensional polar metal by charge transfer to a ferroelectric insulator journal October 2019
Progress and prospects in low-dimensional multiferroic materials journal January 2019
Polar and phase domain walls with conducting interfacial states in a Weyl semimetal MoTe2 journal September 2019
Design of a multifunctional polar metal via first-principles high-throughput structure screening journal February 2020
Strain engineering to facilitate the occurrence of 2D ferroelectricity in CuInP 2 S 6 monolayer journal September 2019
Room-temperature ferroelectricity in MoTe2 down to the atomic monolayer limit journal April 2019
Non-monotonic thickness dependence of Curie temperature and ferroelectricity in two-dimensional SnTe film journal August 2018
Probing ferroelectricity in highly conducting materials through their elastic response: Persistence of ferroelectricity in metallic BaTiO 3 − δ journal February 2019
The emerging ferroic orderings in two dimensions journal November 2019
Synergistic additive-mediated CVD growth and chemical modification of 2D materials journal January 2019
Peculiar piezoelectricity of atomically thin planar structures journal January 2020
Non-monotonic thickness dependence of Curie temperature and ferroelectricity in Two-dimensional SnTe film text January 2018
Van der Waals engineering of magnetism journal October 2019
Nonvolatile Electrical Control and Heterointerface‐Induced Half‐Metallicity of 2D Ferromagnets journal April 2019
Valence mediated tunable magnetism and electronic properties by ferroelectric polarization switching in 2D FeI 2 /In 2 Se 3 van der Waals heterostructures journal January 2019
Switchable Out‐of‐Plane Polarization in 2D LiAlTe 2 journal March 2019
Resistive switching materials for information processing journal January 2020
Observation of the nonlinear Hall effect under time-reversal-symmetric conditions journal December 2018
Heusler interfaces—Opportunities beyond spintronics? journal August 2019
A new criterion for the prediction of solid-state phase transition in TMDs journal January 2019
High electrical conductivity in the epitaxial polar metals LaAuGe and LaPtSb journal December 2019
Nonlinear anomalous Hall effect in few-layer WTe2 journal February 2019
Experimental progress on layered topological semimetals journal April 2019
Experimental Progress on Layered Topological Semimetals text January 2019
A room-temperature ferroelectric semimetal journal July 2019
Vertical ferroelectric switching by in-plane sliding of two-dimensional bilayer WTe 2 journal January 2019
The rise of 2D dielectrics/ferroelectrics journal December 2019
Functional Oxides for Photoneuromorphic Engineering: Toward a Solar Brain journal June 2019
In-plane anisotropic electronics based on low-symmetry 2D materials: progress and prospects journal January 2020
Standing Waves Induced by Valley-Mismatched Domains in Ferroelectric SnTe Monolayers journal May 2019
Tunable magnetic ground states of iron monolayer on nonmagnetic metallic substrates by small in-plane strains journal January 2019
Polar and phase domain walls with conducting interfacial states in a Weyl semimetal MoTe2 text January 2019
Band Signatures for Strong Nonlinear Hall Effect in Bilayer WTe 2 journal December 2018
Room-temperature out-of-plane and in-plane ferroelectricity of two-dimensional β-InSe nanoflakes journal June 2019
MXene Quantum Dot/Polymer Hybrid Structures with Tunable Electrical Conductance and Resistive Switching for Nonvolatile Memory Devices journal November 2019
Switching magnetization with a Weyl semimetal journal August 2019
Design of a multifunctional polar metal via first-principles high-throughput structure screening text January 2019
Recent Progress in Two‐Dimensional Ferroelectric Materials journal November 2019
Interface-induced magnetic polar metal phase in complex oxides journal November 2019
Resistance hysteresis correlated with synchrotron radiation surface studies in atomic sp 2 layers of carbon synthesized on ferroelectric (001) lead zirconate titanate in an ultrahigh vacuum journal January 2020