Phys.org February 1, 2024 An international team of researchers (Germany, USA, Switzerland, UK) studied the time evolution of lattice fluctuations in the quantum paraelectric SrTiO3, in which mid-infrared drives have been shown to induce a metastable ferroelectric state. Crucial in these physics is the competition between polar instabilities and antiferrodistortive rotations, which in equilibrium frustrate the formation of long-range ferroelectricity. They made use of high-intensity mid-infrared optical pulses to resonantly drive the Ti–O-stretching mode at 17?THz, and measured the resulting change in lattice fluctuations using time-resolved X-ray diffuse scattering at a free-electron laser. They observed a long-lived quench in R-point […]
Category Archives: Ferroelectricity
Novel approach to advanced electronics, data storage with ferroelectricity
Phys.org October 16, 2023 Ferroelectrics possess a spontaneous polarization that is switchable by an electric field and is critical for the development of low energy nanoelectronics and neuromorphic applications. However, the realization of switchable polarization in metal oxides with simpler structures has been a major challenge. An international team of researchers (Australia, India) demonstrated the presence of robust switchable polarization at the level of a single nanocrystalline in magnesium-doped zinc oxide thin films with polar wurtzite crystal structures. Voltage control of the polarization and the coupled electronic transport behavior revealed a giant resistance change of approximately 10000% . Time- and […]
Merons and antimerons
Science Daily April 11, 2023 Out-of-plane polar domain structures have recently been discovered in strained and twisted bilayers of inversion symmetry broken systems such as hexagonal boron nitride. An international team of researchers (Belgium, UK, USA – Harvard University) has shown that this symmetry breaking also gives rise to an in-plane component of polarization, and the form of the total polarization is determined purely from symmetry considerations. The in-plane component of the polarization makes the polar domains in strained and twisted bilayers topologically non-trivial, forming a network of merons and antimerons (half-skyrmions and half-antiskyrmions). For twisted systems, the merons are […]
Team demonstrates rare form of electricity in ultra-thin material
Phys.org April 27, 2022 Molybdenum disulfide (MoS2) is known as one of the most promising and robust 2D electronic materials. However, despite theoretical predictions, no ferroelectricity has been experimentally detected in MoS2. An international team of researchers (USA – University of Nebraska, industry, China, France, Luxembourg) has reported the experimental observation of a stable room-temperature out-of-plane polarization ordering in 2D MoS2 layers, where polarization switching is realized by mechanical pressure induced by a tip of a scanning probe microscope. Using this approach, they created the bi-domain polarization states, which exhibit different piezoelectric activity, second harmonic generation, surface potential, and conductivity. […]
New electronic phenomenon discovered
Science Daily August 11, 2021 A team of researchers in the US (University of North Florida, University of Illinois, Arizona State University) has demonstrated a new electronic phenomenon they call “asymmetric ferroelectricity” in atomic layer superlattices constructed using three constituent phases, CaTiO3, SrTiO3 and BaTiO3. The stacking sequence of the atomic layers is found to control the symmetry of the high-temperature dielectric response. When a nanostructured asymmetric strain is programmed into the lattice via the stacking order, the natural symmetry at high temperatures is removed and a polarized sample is obtained in which the polarization increases as the temperature is […]