2009年04月08日

Twist

The spins of a layer of manganese atoms on a tungsten surface from appairal pattern with a unique turning sense. such 'chiral magnetic order' might exist in other, similar contects.

Chirality is a fasinating phenomenon that can manifest itself in subtle ways, for example in biochemistry (in the observed single-handedness of biomolecules) and in particle physis (in the chage-parity violation of electroweak in teractions). (Siegel,J.S. Single-handed cooperation. Nature 409,777-778/2001)(Ellis,J. Antimatter matters. Nature 424,631-634/2003)

In condensed matter, magnetic materials canalso display single-handed, or homochiral, spin tructures. This may be coused by the Dzyaloshinskkii-Moeiya interction, wichi arises from spin-orbit scattering of electrons in an inversion-asymmetric crystal field.(Dzialoshinskii,I.E. Thermodynamic theory of "Weak" ferromagnetism in antiferromagnetic substances. Sov Phys. JETP 5,1259-1262/1957)(Moriya,T. Anistotropic superexchange interaction and weak ferromagetism. phys.Rev. 120,91-98/1960)

This effect is typically irrelevant in bulk metals as their crystals are inversion symmetric. However, low-dimensional systems lack structural inversion summetry, so that homochiral spin structures may occur.(Fert,A. Magnetic and transport properties of metallic multilayers. Mater. Aci froum 59&60, 439-443/1990)

### data ###
Nature 447,115-230 / 2007
Let's twist again / Cristian Pfleiderer and Ulich K. RoBler
Chiral magnetic order at surfaces driven by inversion asymmetry / M Bode et al (University of Hamburg)
posted by 0≠素子 at 09:16| Comment(0) | condensed-matter physics | このブログの読者になる | 更新情報をチェックする
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