Related papers: Reversable phase transitions in ferroic two-dimens…
BaAl$_2$O$_4$ is a ferroelectric material that exhibits structural quantum criticality through chemical composition tuning. Although theoretical calculations and several diffraction experiments have suggested the involvement of a soft mode…
Information technology demands high-speed optoelectronic devices, but going beyond the one terahertz (THz) barrier is challenging due to the difficulties associated with generating, detecting, and processing high-frequency signals. Here, we…
Two-dimensional crystals with coupling of ferroelasticity and attractive electronic properties offer unprecedent opportunities for achieving long-sought controllable devices. But so far, the reported proposals are mainly based on…
Multiferroic materials, known for their multiple tunable orders, present an exceptional opportunity to manipulate nonlinear optical responses, which are sensitive to symmetry. In this study, we propose leveraging electric and magnetic…
A circularly polarized laser pulse can induce persistent intra-molecular currents by either exciting or ionizing molecules. These two cases are identified as electron currents and hole currents, respectively, and up to now they have been…
Transition metal dichalcogenide (TMD) materials have attracted substantial interest due to their remarkable excitonic, optical, electrical, and mechanical properties, which are highly dependent on their crystal structure. Controlling the…
The discovery of two-dimensional (2D) ferroelectrics with switchable out-of-plane polarization such as monolayer $\alpha$-In$_2$Se$_3$ offers a new avenue for ultrathin high-density ferroelectric-based nanoelectronics such as ferroelectric…
We have studied second harmonic generation (SHG) in a polar ferrimagnet GaFeO_3, employing a FeO_6 cluster model in which the Fe atom is slightly shifted from the center of the octahedron. The electric-dipole transition could take place…
In this special issue of Physica A in memory of Professor Dietrich Stauffer, I first recall my impression on him while being his postdoc for a year at HLRZ. In the following scientific part, I discuss the theory of soft phonons with quartic…
We report the direct observation of switching of the N\'eel vector of antiferromagnetic (AFM) domains in response to electrical pulses in micron-scale Pt/$\alpha$-Fe$_2$O$_3$ Hall bars using photoemission electron microscopy. Current pulses…
We show that piezoelectric strain actuation of acoustomechanical interactions can produce large phase velocity changes in an existing quantum phononic platform: aluminum nitride on suspended silicon. Using finite element analysis, we…
Polarized Raman scattering spectra of the K_xCo_{2-y}Se_2 single crystals reveal the presence of two phonon modes, assigned as of the A_{1g} and B_{1g} symmetry. Absence of additional modes excludes the possibility of vacancy ordering,…
Layers of perovskites, found in 3D materials, 2D heterostructures, and nanotubes, often distort from high symmetry to facilitate dipole polarisation that is exploitable in many applications. Using density-functional theory calculations,…
Deterministic polarization reversal in ferroelectric and multiferroic films is critical for their exploitation in nanoelectronic devices. While ferroelectricity has been studied for nearly a century, major discrepancies in the reported…
Two-dimensional (2D) Ruddlesden-Popper (RP) Metal Halides present unique and tunable properties. However, direct and oriented synthesis is challenging due to low formation energies that lead to rapid, uncontrolled growth during…
The reversible phase transition between orthorhombic and cubic phases is demonstrated in all-inorganic perovskite CsPbIBr2 grown by a dual-source vapor-deposition method. The phase transition is actuated via heating and moisture exposure.…
We report the first principles investigations on the phonons of three polytypes of BaTiO3 (BTO): paraelectric (PE) cubic Pm-3m and two ferroelectric (FE) phases, tetragonal P4mm and rhombohedral R3m. The phonon frequencies calculated using…
I propose a method for ultrafast switching of ferroelectric polarization using mid-infrared pulses. This involves selectively exciting the highest frequency $A_1$ phonon mode of a ferroelectric material with an intense mid-infrared pulse.…
Ferroelasticity describes a phenomenon in which a material exhibits two or more equally stable orientation variants and can be switched from one form to another under an applied stress. Recent works have demonstrated that two-dimensional…
The reversible phase transition induced by femtosecond laser excitation of Gallium has been studied by measuring the dielectric function at 775 nm with ~ 200 fs temporal resolution. The real and imaginary parts of the transient dielectric…