TY - JOUR
KW - Simulation
KW - Steady state
KW - Polarization
KW - Electric field
KW - Chemical structure
KW - Electrical parameters
KW - Priority journal
KW - Electric capacitance
KW - Letter
KW - Scanning transmission electron microscopy
KW - X-ray Diffraction
KW - Energy density
KW - Ferroelectric dielectric heterostructure
KW - Negative capacitance
AU - A.K Yadav
AU - K.X Nguyen
AU - Z Hong
AU - P García-Fernández
AU - P Aguado-Puente
AU - C.T Nelson
AU - S Das
AU - B Prasad
AU - D Kwon
AU - S Cheema
AU - A.I Khan
AU - C Hu
AU - J Íñiguez
AU - J Junquera
AU - L.-Q Chen
AU - D.A Muller
AU - Ramamoorthy Ramesh
AU - S Salahuddin
AB - Negative capacitance is a newly discovered state of ferroelectric materials that holds promise for electronics applications by exploiting a region of thermodynamic space that is normally not accessible1–14. Although existing reports of negative capacitance substantiate the importance of this phenomenon, they have focused on its macroscale manifestation. These manifestations demonstrate possible uses of steady-state negative capacitance—for example, enhancing the capacitance of a ferroelectric–dielectric heterostructure4,7,14 or improving the subthreshold swing of a transistor8–12. Yet they constitute only indirect measurements of the local state of negative capacitance in which the ferroelectric resides. Spatial mapping of this phenomenon would help its understanding at a microscopic scale and also help to achieve optimal design of devices with potential technological applications. Here we demonstrate a direct measurement of steady-state negative capacitance in a ferroelectric–dielectric heterostructure. We use electron microscopy complemented by phase-field and first-principles-based (second-principles) simulations in SrTiO3/PbTiO3 superlattices to directly determine, with atomic resolution, the local regions in the ferroelectric material where a state of negative capacitance is stabilized. Simultaneous vector mapping of atomic displacements (related to a complex pattern in the polarization field), in conjunction with reconstruction of the local electric field, identify the negative capacitance regions as those with higher energy density and larger polarizability: the domain walls where the polarization is suppressed. © 2019, Springer Nature Limited.
BT - Nature
DO - 10.1038/s41586-018-0855-y
LA - eng
M1 - 7740
N1 - cited By 35
N2 - Negative capacitance is a newly discovered state of ferroelectric materials that holds promise for electronics applications by exploiting a region of thermodynamic space that is normally not accessible1–14. Although existing reports of negative capacitance substantiate the importance of this phenomenon, they have focused on its macroscale manifestation. These manifestations demonstrate possible uses of steady-state negative capacitance—for example, enhancing the capacitance of a ferroelectric–dielectric heterostructure4,7,14 or improving the subthreshold swing of a transistor8–12. Yet they constitute only indirect measurements of the local state of negative capacitance in which the ferroelectric resides. Spatial mapping of this phenomenon would help its understanding at a microscopic scale and also help to achieve optimal design of devices with potential technological applications. Here we demonstrate a direct measurement of steady-state negative capacitance in a ferroelectric–dielectric heterostructure. We use electron microscopy complemented by phase-field and first-principles-based (second-principles) simulations in SrTiO3/PbTiO3 superlattices to directly determine, with atomic resolution, the local regions in the ferroelectric material where a state of negative capacitance is stabilized. Simultaneous vector mapping of atomic displacements (related to a complex pattern in the polarization field), in conjunction with reconstruction of the local electric field, identify the negative capacitance regions as those with higher energy density and larger polarizability: the domain walls where the polarization is suppressed. © 2019, Springer Nature Limited.
PB - Nature Publishing Group
PY - 2019
SP - 468
EP - 471
T2 - Nature
TI - Spatially resolved steady-state negative capacitance
VL - 565
SN - 00280836
ER -