Video Experimental Relacionado
Updated: Jul 1, 2026
11:54
Growth and Electrostatic/chemical Properties of Metal/LaAlO3/SrTiO3 Heterostructures
Published on: February 8, 2018
Pruebas para el transporte de carga unidimensional en La{2-x-y) Nd{y) Sr{x) CuO{4)
1Department of Superconductivity, The University of Tokyo, Tokyo 113-8656, Japan.
Science (New York, N.Y.)
|October 9, 1999
Resumen
Este estudio revela un cambio en el transporte de carga en el lantano dopado con neodimio y cuprato de estroncio. A bajos niveles de dopaje, el transporte es unidimensional, cambiando a dos dimensiones en concentraciones más altas.
Área de la Ciencia:
- Física de la materia condensada Física de la materia condensada
- Ciencia de los materiales Ciencia de los materiales.
- Química del estado sólido.
Sus antecedentes:
- El cuprato de estroncio de lantano dopado con neodimio (La{1.4-x) Nd{0.6) Sr{x) CuO{4)) exhibe propiedades electrónicas complejas.
- Comprender los mecanismos de transporte de carga es crucial para el desarrollo de materiales electrónicos avanzados.
Objetivo del estudio:
- Para investigar la dependencia de dopaje de la resistividad y el coeficiente de Hall en La{1.4-x) Nd{0.6) Sr{x) CuO{4).
- Para aclarar la naturaleza del transporte de carga dentro de la banda de carga de giro estática ordenada fase.
Principales métodos:
- Medidas de la resistividad y el coeficiente de Hall en función de la concentración de dopaje (x).
- Análisis del comportamiento de transporte de carga en la franja de carga-espín estática en fase ordenada.
Principales resultados:
- Una rápida disminución en la magnitud del coeficiente de Hall a bajas temperaturas (x <= 1/8) indica un transporte de carga unidimensional.
- Para concentraciones de dopaje más altas (x > 1/8), el coeficiente de Hall permanece alto en la fase ordenada.
- Evidencia de un cruce del transporte de carga unidimensional al bidimensional en x = 1/8.
Conclusiones:
- La concentración de dopaje influye críticamente en la dimensionalidad del transporte de carga en este material.
- Un punto de cruce distinto en x = 1/8 separa los regímenes de transporte unidimensional y bidimensional.
- Estos hallazgos ofrecen información sobre el diagrama electrónico de fases de los superconductores de cuprato.
Videos de Conceptos Relacionados
02:54Trends in Lattice Energy: Ion Size and Charge
An ionic compound is stable because of the electrostatic attraction between its positive and negative ions. The lattice energy of a compound is a measure of the strength of this attraction. The lattice energy (ΔHlattice) of an ionic compound is defined as the energy required to separate one mole of the solid into its component gaseous ions. For the ionic solid sodium chloride, the lattice energy is the enthalpy change of the process:
02:42Ionic Crystal Structures
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
03:02Colors and Magnetism
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
01:17Theory of Metallic Conduction
The conduction of free electrons inside a conductor is best described by quantum mechanics. However, a classical model makes predictions close to the results of quantum mechanics. It is called the theory of metallic conduction.
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
01:29Electrical Transport
The electrical transport property of a material is defined by its resistance and conductivity. Resistance is the measure of a material's ability to resist the flow of electric current, while conductivity gauges its ability to allow the current to pass through, depending on the geometry of the measurement cell, such as electrode spacing and area. Conductivity is measured in Siemens (S). There are different types of conductance, including specific conductance, equivalent conductance, and molar...
01:30The Electrical Double Layer
In the region where two bulk phases meet, an intricate electric charge distribution arises due to charge transfer, ion adsorption, molecular orientation, and charge distortion. This complex distribution is commonly referred to as the electrical double layer.When a solid electrode interfaces with ions in an electrolyte solution, the speed of electron transfer dictates the rates of oxidation and reduction. The electrode acquires a charge through the escape of atoms into the solution as cations or...