This shows the electron distribution for dislocation cores in molybdenum (Mo). The disolcations are screws along <111> which is the axis coming out of the page. The picture has four dislocations in it. Three values of electron density are shown as isosurfaces: low density (blue), medium density (purple), and high density (orange). Mo is a metal, as exemplified by the low electron density that is quite uniform throughout the system. The high density regions highlight the strongly bound d-states of Mo: the nuclei are within each of the orange cube-like surfaces (cubes have eight corners, and Mo in the bcc phase has eight nearest neighbors pointing at the cube corners). The medium density perturbations are localized about the dislocation cores, showing the perturbations caused to the electronic structure of the system. Reference: S. Ismail-Beigi and T. A. Arias, "Ab Initio Study of Screw Dislocations in Mo and Ta: A new picture of plasticity in bcc transition metals", Physical Review Letters 84, 1499 (2000).

Submitted by Sohrab Ismail-Beigi