# Dresden 2014 – wissenschaftliches Programm

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# HL: Fachverband Halbleiterphysik

## HL 90: Low-dimensional systems: Topological order (organized by TT)

### HL 90.5: Vortrag

### Donnerstag, 3. April 2014, 10:30–10:45, HSZ 204

**Topological phase transition in the Kitaev-Ising ladder** — Amir Mohammad-Aghaie^{1}, Reza Haghshenas^{1}, and •Abdollah Langari^{1,2} — ^{1}Department of Physics, Sharif University of Technology, P.O.Box 11155-9161, Tehran, Iran — ^{2}Max-Planck-Institut fuer Physik komplexer Systeme, 01187 Dresden, Germany

We have studied the Kitaev-Ising model on a ladder geometry using iDMRG algorithm. We find a quantum phase transition between the Kitaev and Ising phases whenever the ratio of Ising to Kitaev coupling is exactly equal to 1/2. The divergence in the von-Neumann entropy and the change of degeneracy in the entanglement spectrum justifies the symmetry protected topological phase (SPT) transition. We investigate the robustness of the SPT phase in the presence of cluster terms which preserve/break the symmetry of the model. We also discuss the effect of Ising terms on the legs of ladder in addition to the rhombic interaction, which leads to frustration for the antiferromagnetic interactions.