FeRAM ( Ferroelectric RAM )

Ferroelectric capacitors is a molecular dynamics simulator for bulk and thin-film ferroelectrics and relaxors possess the characteristics necessary for a nonvolatile memory cell, that is they have stable states corresponding to the binary levels in a digital memory, and they retain their states without electrical power. Although similar characteristics exist in ferromagnetic cores of a core memory, ferroelectric capacitors switch faster and they may even be fabricated on a single VLSI chip.


Each cell in the core array can be selected by simultaneous X and Y current pulses. The cells that are receiving (or none) of these current pulses stay unselected. The cell that is receiving both X and Y current pulses flips to its opposite magnetization state or stay unchanged, depending on its preliminary magnetization state and the current pulse directions. A similar situation exists in the array of FE capacitors. In fact, the above statements can be applied to the capacitor array if the terms current and magnetization are replaced by their counterparts voltage and polarization, respectively.


The capacitor array forms the simplest and the densest cell structure among ferroelectric nonvolatile memory designs. However, more complex structures are necessary due to nonideal characteristics of ferroelectric capacitors. of these characteristics is the dearth of a one-of-a-kind switching voltage. Partial switching can occur within a range of applied voltage. If this range is wide , the cells that are in the same row (or column) as the selected cell can be disturbed by X (or Y) voltage pulses. The effects of these partial switchings in an unselected cell can add up and damage the stored information.


In Physics : 

• Molecular dynamics (MD) simulation with a first-principles-based model Hamiltonian
• Ferroelectrics
• Relaxor
• Phase transition
• Narrow film
• Electrodes
• Capacitor
• Hysteresis loop
• Nose-Poincare thermostat
• Optical phonon
• Evaluate forces in reciprocal-space; k-locality of the force matrix
• Coarse-graining; reduction of the number of degree of freedom