Topic
Landau theory
About: Landau theory is a research topic. Over the lifetime, 2882 publications have been published within this topic receiving 57078 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: In this article, the O(N)-equivariant vortex solution for Ginzburg-Landau type equations in the N-dimensional Euclidean space is characterized and its local energy minimality for the corresponding energy functional is proved.
24 citations
TL;DR: In this article, a temperature-misfit strain phase diagram of a BaTiO3 thin film derived with high-order electromechanical interactions was evaluated using first-principles calculations.
Abstract: Currently used methods for the description of thermodynamics of ferroelectric thin films (Landau theory or ab initio based Monte Carlo simulations) are based on an energy expansion in terms of internal degrees of freedom. It was shown that these methods can suffer from a substantial inaccuracy unless higher order electromechanical interactions are taken into account. The high-order electromechanical couplings strongly renormalize the sixth-power polarization terms of the thermodynamic energy expansion. In this paper, apart from the general statement, we illustrate it with an example of a temperature-misfit strain phase diagram of a BaTiO3 thin film derived with high-order electromechanical interactions evaluated using first-principles calculations.
23 citations
TL;DR: In this article, a simple Landau model was used to calculate magnetization isotherms considering magnetic hysteresis, and the model parameters were chosen to fit the magnetic and magnetocaloric data of MnAs compound.
Abstract: We have explored a simple Landau model to calculate magnetization isotherms considering magnetic hysteresis. The model parameters have been chosen to fit the magnetic and magnetocaloric data of MnAs compound. Experimental data show that there is a great difference between the isothermal variation of the entropy (ST) obtained from isotherms measured increasing and decreasing magnetic field. This great difference is reproduced theoretically. From the experimental and phenomenological isotherms, we calculated the ST. From the theoretical entropy, we also obtained ST, which does not present the colossal peak.
23 citations
TL;DR: In this article, temperature dependence of the dielectric constant in this temperature range has been explained applying the Landau theory, and no indication of any phase transition was obtained near 170 K.
Abstract: Measurement of the dielectric constant and optical observation of domain structure in (CH 3 NH 3 ) 5 Bi 2 Cl 11 have been carried out in the temperature range including 170 K, which has been regarded as a transition temperature. No indication of any phase transition was obtained near 170 K. Temperature dependence of the dielectric constant in this temperature range has been explained applying the Landau theory.
23 citations
03 Apr 2017
TL;DR: In this article, the authors extended the Landau model to describe more than one domain, and showed how an internal metal electrode inherently destabilizes negative capacitance (NC) in a transistor gate stack.
Abstract: Stabilization of ferroelectric negative capacitance (NC) in a transistor gate stack is a promising pathway towards future low power electronics. However, most modeling efforts of such NCFETs are based on single-domain Landau theory, which is an oversimplification that leads to incorrect predictions and device design. By extending the Landau model to describe more than one domain, it is shown how an internal metal electrode inherently destabilizes NC. Consequently, NCFETs have to be designed without internal metal electrode to function. Furthermore, the use of single-domain Landau theory to model NCFETs with HfO 2 based ferroelectrics is critically discussed.
23 citations