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  2. Density of states - Wikipedia

    en.wikipedia.org/wiki/Density_of_states

    The density of states related to volume V and N countable energy levels is defined as: = = (()). Because the smallest allowed change of momentum for a particle in a box of dimension and length is () = (/), the volume-related density of states for continuous energy levels is obtained in the limit as ():= (()), Here, is the spatial dimension of the considered system and the wave vector.

  3. Van Hove singularity - Wikipedia

    en.wikipedia.org/wiki/Van_Hove_singularity

    The density of states which appears in the Fermi's Golden Rule expression is then the joint density of states, which is the number of electronic states in the conduction and valence bands that are separated by a given photon energy.

  4. Quantum dot - Wikipedia

    en.wikipedia.org/wiki/Quantum_dot

    The energy levels of a single particle in a quantum dot can be predicted using the particle in a box model in which the energies of states depend on the length of the box. For an exciton inside a quantum dot, there is also the Coulomb interaction between the negatively charged electron and the positively charged hole.

  5. Energy applications of nanotechnology - Wikipedia

    en.wikipedia.org/wiki/Energy_applications_of...

    The Li-ion battery is currently one of the most popular electrochemical energy storage systems and has been widely used in areas from portable electronics to electric vehicles. [15] [16] However, the gravimetric energy density of Li-ion batteries is limited and less than that of fossil fuels. The lithium sulfur (Li-S) battery, which has a much ...

  6. Scanning tunneling spectroscopy - Wikipedia

    en.wikipedia.org/wiki/Scanning_tunneling...

    Mechanism of how density of states influence V-A spectra of tunnel junction. Scanning tunneling spectroscopy is an experimental technique which uses a scanning tunneling microscope (STM) to probe the local density of electronic states (LDOS) and the band gap of surfaces and materials on surfaces at the atomic scale. [1]

  7. Density matrix - Wikipedia

    en.wikipedia.org/wiki/Density_matrix

    In quantum mechanics, a density matrix (or density operator) is a matrix that describes an ensemble [1] of physical systems as quantum states (even if the ensemble contains only one system). It allows for the calculation of the probabilities of the outcomes of any measurements performed upon the systems of the ensemble using the Born rule .

  8. Density functional theory - Wikipedia

    en.wikipedia.org/wiki/Density_functional_theory

    The functional that delivers the ground-state energy of the system gives the lowest energy if and only if the input density is the true ground-state density. In other words, the energy content of the Hamiltonian reaches its absolute minimum, i.e., the ground state, when the charge density is that of the ground state.

  9. Electronic entropy - Wikipedia

    en.wikipedia.org/wiki/Electronic_entropy

    Insulators have zero density of states at the Fermi level due to their band gaps. Thus, the density of states-based electronic entropy is essentially zero in these systems. Metals have non-zero density of states at the Fermi level. Metals with free-electron-like band structures (e.g. alkali metals, alkaline earth metals, Cu, and Al) generally ...