Spin density wave

Spin-density wave (SDW) and charge-density wave (CDW) are names for two similar low-energy ordered states of solids. Both these states occur at low temperature in anisotropic, low-dimensional materials or in metals that have high densities of states at the Fermi level ${\displaystyle N(E_{F})}$. Other low-temperature ground states that occur in such materials are superconductivity, ferromagnetism and antiferromagnetism. The transition to the ordered states is driven by the condensation energy which is approximately ${\displaystyle N(E_{F})\Delta ^{2}}$ where ${\displaystyle \Delta }$ is the magnitude of the energy gap opened by the transition. Note that SDWs are distinct from spin waves, which are an excitation mode of ferromagnets and antiferromagnets.

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