Ferroelectricity and phase transitions in In2Se3 van der Waals material

Nanoscale ◽  
2020 ◽  
Vol 12 (44) ◽  
pp. 22688-22697
Author(s):  
Maryam Soleimani ◽  
Mahdi Pourfath
Keyword(s):  
Phase Transitions ◽  
Electric Field ◽  
Applied Electric Field ◽  
Room Temperature ◽  
Van Der Waals ◽  
Out Of Plane

Van der Waals layered α-In2Se3 has shown out-of-plane ferroelectricity down to the bilayer and monolayer thicknesses at room temperature that can be switched by an applied electric field.

scholarly journals Current-Induced Spin Photocurrent in GaAs at Room Temperature

Sensors ◽  
2022 ◽  
Vol 22 (1) ◽  
pp. 399
Author(s):  
Yang Zhang ◽  
Yu Liu ◽  
Xiao-Lan Xue ◽  
Xiao-Lin Zeng ◽  
Jing Wu ◽  
...  
Keyword(s):  
Electric Field ◽  
Spin Polarization ◽  
Applied Electric Field ◽  
Room Temperature ◽  
Polarization Direction ◽  
Applied Bias ◽  
Applied Bias Voltage ◽  
Sample Plane ◽  
Bulk Gaas ◽  
Circularly Polarized

Circularly polarized photocurrent, observed in p-doped bulk GaAs, varies nonlinearly with the applied bias voltage at room temperature. It has been explored that this phenomenon arises from the current-induced spin polarization in GaAs. In addition, we found that the current-induced spin polarization direction of p-doped bulk GaAs grown in the (001) direction lies in the sample plane and is perpendicular to the applied electric field, which is the same as that in GaAs quantum well. This research indicates that circularly polarized photocurrent is a new optical approach to investigate the current-induced spin polarization at room temperature.

Positron annihilation in methane

1977 ◽  
Vol 55 (3) ◽  
pp. 235-239 ◽  
Author(s):  
A. C. Mao ◽  
D. A. L. Paul
Keyword(s):  
Electric Field ◽  
Positron Annihilation ◽  
Applied Electric Field ◽  
Room Temperature ◽  
Positive Energy ◽  
Annihilation Rate ◽  
Linear Region ◽  
Gas Density ◽  
Single Level ◽  
Made In

Measurements of positron annihilation rates at room temperature under the influence of an applied electric field have been made in methane at different pressures. The experiments were all carried out in the linear region in which the annihilation rate is accurately proportional to gas density. We find Zeff = 142.7 ± 2.0 at 21 °C and zero electric field. At 1000 Torr Zeff decreases linearly with the electric field, the gradient being about 2.5 × 10−2 per (V cm−1 atm−1) at that temperature. The results repudiate the idea of a positive energy single level Breit–Wigner resonance as being responsible for the high value of Zeff, and in this sense are in agreement with the findings of McNutt, Summerour, Ray, and Huang.

Tunable electronic properties in the van der Waals heterostructure of germanene/germanane

2015 ◽  
Vol 17 (18) ◽  
pp. 12194-12198 ◽  
Author(s):  
Run-wu Zhang ◽  
Chang-wen Zhang ◽  
Wei-xiao Ji ◽  
Feng Li ◽  
Miao-juan Ren ◽  
...  
Keyword(s):  
Electric Field ◽  
Band Gap ◽  
Electronic Properties ◽  
External Electric Field ◽  
High Performance ◽  
Room Temperature ◽  
Van Der Waals ◽  
Van Der Waals Heterostructure ◽  
Structural And Electronic Properties

We investigate the structural and electronic properties of germanene/germanane heterostructures. The band gap in these heterostructures can be effectively modulated by the external electric field and strain. These results provide a route to design high-performance FETs operating at room temperature in nanodevices.

scholarly journals Modulation Electronic Properties of Silicane/SnSe2 Van der Waals Heterostructures Using External Force and Electric Field

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Gang Xu ◽  
Yelu He
Keyword(s):  
Electric Field ◽  
Applied Electric Field ◽  
High Performance ◽  
Van Der Waals ◽  
Type I ◽  
Normal Strain ◽  
Van Der Waals Heterostructures ◽  
Electronic Band ◽  
Fundamental Research ◽  
Metal Phase Transition

In recent years, much interest in the study of Van der Waals heterostructures (vdWhs) has arisen. This has led to a significant amount of fundamental research being produced, from which novel optoelectronic applications have been established. By using first principles, we analyze the electronic structure of silicane/SnSe2 vdWhs in the response to an externally applied electric field and a normal strain. The results show that the silicane/SnSe2 vdWh acts as an indirect semiconductor when it is subjected to an applied electric field between −1 and 0.1 V/Å and becomes a metal in the 0.2 to 1 V/Å range. Significantly, the electronic band alignments of the silicane/SnSe2 vdWhs are modified from a type-II to a type-I when a field of −0.7 V/Å is applied. Furthermore, it is determined that the silicane/SnSe2 vdWhs appears to have a semiconductor-metal phase transition at a strain of −5%. Our results indicate that the silicane/SnSe2 vdWhs have the potential for applications in novel high-performance optoelectronic devices.

Electrooptic study of antiferroelectric mixtures for display application

2006 ◽  
Vol 14 (4) ◽  
Author(s):  
A. Mikułko ◽  
M. Marzec ◽  
S. Wróbel ◽  
R. Dąbrowski
Keyword(s):  
Field Theory ◽  
Phase Transitions ◽  
Electric Field ◽  
Tilt Angle ◽  
Spontaneous Polarization ◽  
Room Temperature ◽  
Mean Field Theory ◽  
Mean Field ◽  
Current Method ◽  
Range Measurements

AbstractThe aim of this paper is to study the influence of electric field on alignment of para-, ferro- and antiferroelectric phases in the vicinity of SmA* — SmC* or SmC* — SmCA* phase transitions as to obtain mono-domain cells. Four mixtures studied (W-193B, W-193B-1, W-201, W-204D) show the SmCA* phase in a wide room temperature range. Measurements of the spontaneous polarization versus temperature by using reversal current method give an answer to the question, what kind of the transitions take place between para-, ferro- or antiferroelectric phases using the Landau mean field theory. Optimal electrooptic parameters for different compositions of the mixtures such as tilt angle, spontaneous polarization and saturation voltage have been measured to compare parameters of the mixtures studied.

Strain Actuation Behavior of Barium Titanate Single Crystal Loaded Electromechanically in Non-Variant [110] Direction

2012 ◽  
Author(s):  
Jay Shieh ◽  
Yen-Nan Lin ◽  
Yi-Chung Shu
Keyword(s):  
Barium Titanate ◽  
Electric Field ◽  
Single Crystal ◽  
Electric Fields ◽  
Room Temperature ◽  
Hexagonal Prism ◽  
Simultaneous Application ◽  
Strain Behavior ◽  
Bias Stress ◽  
Out Of Plane

Strain hysteresis evolution of a (001)-oriented 5 × 5 × 2 mm3 cuboidal barium titanate (BaTiO3) single crystal during a combined electromechanical loading sequence in the non-variant [110] direction is investigated. The goal is to compare the strain behaviors of the BaTiO3 single crystal subjected to loading in the variant [001] and non-variant [110] directions. The simultaneous application of compressive stress and electric field in the [110] direction was achieved by machining the square cuboid crystal into a hexagonal prism and applying the loads parallel to the hexagonal side faces of the prism (i.e., perpendicular to the [001] and 45° to the [100] and [010] directions). The room temperature strain hystereses show that the maximum total electro strains produced from loading and measuring in the [110] and [001] directions (denoted as ε[110],max,RT and ε[001],max,RT, respectively, where the last term of the subscript describes the testing temperature) are 0.20% at 3.0 MPa and 0.45% at 2.7 MPa, respectively. The ratio between ε[110],max,RT and ε[001],max,RT is 0.44, which is in good agreement with the ratio, predicated by the analytical calculations. Factors which may influence the strain behavior, such as the bias stress level, depolarization field and switching coercivities, are examined by repeating the loading experiment at 55 °C. The strain hystereses measured at 55 °C show that ε[110],max,55 is 0.19% at 11.9 MPa — this maximum [110] strain is similar to the one obtained at room temperature, but is only achieved with a much larger bias stress. When the out-of-plane depolarization field and the in-plane switching coercivities are reduced at 55 °C, more domains are randomized in the in-plane variant directions during electric field unloading by the depolarization fields. Therefore, a much larger bias stress is required at 55 °C to switch a sufficient number of domains to the out-of-plane variant directions at small electric fields, which can then be switched back to the in-plane variant directions at high electric fields, producing strain in the [110] direction. The strain hysteresis study has revealed that the combined effect of the depolarization field and switching coercivity is a critical factor governing the strain behavior of the BaTiO3 single crystal.

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