Possible quadrupole-order-driven commensurate-incommensurate phase transition in B20 CoGe

The Commensurate Incommensurate Transition

In condensed matter physics there are many successful models of phase transitions between a more ordered and less ordered state. Break a continuous symmetry and you’ve got yourself a cpmtomipus phase transition. Roughly speaking the transition occurs when the symmetry breaking potential term becomes the dominant one in the free energy and the system ‘contracts’ in phase space decreasing entropy...

Commensurate–incommensurate transition in graphene on hexagonal boron nitride

When a crystal is subjected to a periodic potential, under certain circumstances it can adjust itself to follow the periodicity of the potential, resulting in a commensurate state. Of particular interest are topological defects between the two commensurate phases, such as solitons and domain walls. Here we report a commensurate–incommensurate transition for graphene on top of hexagonal boron ni...

Commensurate-incommensurate magnetic phase transition in magnetoelectric single crystal LiNiPO(4).

Neutron scattering studies of single crystal LiNiPO4 reveal a spontaneous first-order commensurate-incommensurate magnetic phase transition. Short- and long-range incommensurate phases are intermediate between the high temperature paramagnetic and the low temperature antiferromagnetic phases. The modulated structure has a predominant antiferromagnetic component, giving rise to satellite peaks i...

Commensurate-incommensurate transition for graphene on hexagonal boron nitride

Dislocation Structures of Submonolayer Films near the Commensurate-Incommensurate Phase Transition: Ag on Pt(111)

Submonolayer films of Ag on Pt(111) exhibit parallel partial dislocations separated by narrow hcp domains and much wider fcc domains, the large difference in width being atypical of strained metal overlayers on close-packed substrates. Using a two-dimensional Frenkel-Kontorova model, we calculate the relative domain widths. We examine possible effects of dislocations on equilibrium island shape...