quasieindimensionaler

Quasieindimensionaler, or quasi-one-dimensional, describes a physical system in which motion along one spatial direction dominates while motion in the remaining directions is strongly confined or weakly coupled. In practice, this means that electrons, spins, or other excitations propagate primarily along a preferred axis, but with some finite coupling to transverse directions. The term is commonly used in condensed-m matter physics to characterize materials or structures whose electronic structure and collective behavior resemble one dimension, even though they are not strictly one-dimensional.

A typical realization involves strong confinement in two directions, such that electrons occupy only a few transverse subbands. If the coupling between adjacent chains, wires, or channels is small compared with the intrachain dynamics, the system behaves as effectively one-dimensional over a broad range of temperatures or energies. The electronic dispersion can often be written as E(k) = ε(kx) + t⊥(ky, kz), with t⊥ ≪ bandwidth along x. As a result, the Fermi surface consists of warped sheets, reflecting the weak interchain connectivity.

Theoretical descriptions usually start from one-dimensional models, such as the Luttinger liquid, and consider weak transverse couplings that can drive a dimensional crossover to higher-dimensional behavior at low temperatures. Quasieindimensional systems commonly exhibit anisotropic transport, density-wave instabilities (charge or spin), and, under favorable conditions, unconventional superconductivity along the principal axis. The crossover to higher dimensionality can lead to a transition from non-Fermi-liquid to Fermi-liquid-like behavior as temperature or coupling changes.

Prominent examples include organic conductors of the Bechgaard and Fabre salts, TTF-TCNQ, certain transition-metal trichalcogenides, carbon nanotubes, and engineered cold-atom lattices.