80
2 Fundamental Properties of Mem-Elements
expected to have impact in two major areas: (1) modular, low-power materials that
could interface with cells and tissues for biosensing and processing of biological
signals due to their soft and biocompatible nature; and (2) as a model system to
study capacitive excitability in neuronal membranes.
Appendix 1: Memristive Devices: Materials and Complex
Physics
The axiomatic approach introduced in Chap. 1 suggests that a realistic circuit model
of any molecular/nanodevice will in general require an appropriate interconnection
of building blocks chosen from the periodic table of ideal circuit elements. In this
context, the “concept of ideal memristor” as introduced by L. O. Chua in 1971 [2] is
useful as long as it permits to capture with a suitable degree of accuracy and within
a broad range of operation the electrical behavior at the external terminals of real
memristor devices. Thus, the intent of ideal memristor is to be useful in the design
of a circuit model of real devices (e.g., the Josephson junction in Example 1.9 of
Chap. 1). Such concepts can be also used to conceive a systematic modus operandi
for tuning chemical/physical properties of materials to approximate under suitable
conditions an ideal memristor and to empower real memristor devices with novel
computation and information processing potentials.
Although the main focus of the book is on nonlinear dynamical circuits and
systems including ideal mem-elements, this section aims to provide a basic summary of inorganic/organic materials, nanoscale/molecular structures, and physical
phenomena giving rise to an electrical behavior ascribed to memristor. The complexity of technological realizations and of chemical/physical processes results
in physical/behavioral models that keep the structure of the original idealized
memristor [2] and encapsulate the distinctive property of tuning the resistive state
according to the history of the applied input (voltage or current). Along this line, in
2008, researchers at HP headed by S. Williams were the first to show, by “using a
simple analytical example, that memristance arises naturally in nanoscale systems
in which solid-state electronic and ionic transport are coupled under an external
bias voltage” [28]. The resistive state of the HP memristor is modulated by the
bias voltage applied across two Pt electrodes of a metal-insulator-metal structure
because the electric field is capable of shifting the interface between TiO 2 and
TiO 2−x due to the migration of oxygen vacancies (see Sect. 2.5.3 for more details).
Since 2008, memristor conceptualization has attracted the attention of many
researchers in different fields ranging from material science, storage memory
devices, nonlinear circuits and complex systems, and unconventional/neuromorphic
computing architectures. During the last decade several review works and books
have been published in material science and neuromorphic systems. The remaining
part of this section gives a compendious list of material structures and physical
factors that influence the motion of electron/ion charges for: (a) drift phenomena
2 Fundamental Properties of Mem-Elements
expected to have impact in two major areas: (1) modular, low-power materials that
could interface with cells and tissues for biosensing and processing of biological
signals due to their soft and biocompatible nature; and (2) as a model system to
study capacitive excitability in neuronal membranes.
Appendix 1: Memristive Devices: Materials and Complex
Physics
The axiomatic approach introduced in Chap. 1 suggests that a realistic circuit model
of any molecular/nanodevice will in general require an appropriate interconnection
of building blocks chosen from the periodic table of ideal circuit elements. In this
context, the “concept of ideal memristor” as introduced by L. O. Chua in 1971 [2] is
useful as long as it permits to capture with a suitable degree of accuracy and within
a broad range of operation the electrical behavior at the external terminals of real
memristor devices. Thus, the intent of ideal memristor is to be useful in the design
of a circuit model of real devices (e.g., the Josephson junction in Example 1.9 of
Chap. 1). Such concepts can be also used to conceive a systematic modus operandi
for tuning chemical/physical properties of materials to approximate under suitable
conditions an ideal memristor and to empower real memristor devices with novel
computation and information processing potentials.
Although the main focus of the book is on nonlinear dynamical circuits and
systems including ideal mem-elements, this section aims to provide a basic summary of inorganic/organic materials, nanoscale/molecular structures, and physical
phenomena giving rise to an electrical behavior ascribed to memristor. The complexity of technological realizations and of chemical/physical processes results
in physical/behavioral models that keep the structure of the original idealized
memristor [2] and encapsulate the distinctive property of tuning the resistive state
according to the history of the applied input (voltage or current). Along this line, in
2008, researchers at HP headed by S. Williams were the first to show, by “using a
simple analytical example, that memristance arises naturally in nanoscale systems
in which solid-state electronic and ionic transport are coupled under an external
bias voltage” [28]. The resistive state of the HP memristor is modulated by the
bias voltage applied across two Pt electrodes of a metal-insulator-metal structure
because the electric field is capable of shifting the interface between TiO 2 and
TiO 2−x due to the migration of oxygen vacancies (see Sect. 2.5.3 for more details).
Since 2008, memristor conceptualization has attracted the attention of many
researchers in different fields ranging from material science, storage memory
devices, nonlinear circuits and complex systems, and unconventional/neuromorphic
computing architectures. During the last decade several review works and books
have been published in material science and neuromorphic systems. The remaining
part of this section gives a compendious list of material structures and physical
factors that influence the motion of electron/ion charges for: (a) drift phenomena