Ground State Phase Diagram of the Spin S=1/2 XXZ Heisenberg Chain with Alternating Dzyaloshinskii-Moriya Interaction
Prof. George Japaridze
Georgian National Academy of Sciences, Andronikashvili Institute of Physics

The ground state phase diagram of a spin S=1/2 XXZ Heisenberg chain with spatially modulated Dzyaloshinskii-Moriya (DM) interaction


is studied using the continuum-limit bosonization approach and density matrix renormalization group computations. It is shown that at clip_image004.png the effective continuum-limit bosonized theory of the model is given by the double frequency sine-Gordon model (DSG) where the frequencies i.e. the scaling dimensions of the two competing cosine perturbation terms depend on the effective anisotropy parameter clip_image006.png. Exploring the ground state properties of the DSG model is show that the zero-temperature phase diagram contains the following four phases: (i) the ferromagnetic phase (FM) at clip_image008.png (ii) the gapless Luttinger-liquid (LL) phase at clip_image010.png(iii) the gapped composite (C1) phase characterized by coexistence of the long-range-ordered (LRO) dimerization pattern clip_image012.png with the LRO alternating spin chirality pattern clip_image014.png at clip_image016.png and (iv) at at clip_image018.png the gapped composite (C2) phase characterized in addition to the coexisting spin dimerization and alternating chirality patterns, by the presence of LRO antiferromagnetic order. The transition from the LL to the C1 phase at clip_image020.png belongs to the Berezinskii-Kosterlitz-Thouless universality class, while the transition at clip_image022.png from C1 to C2 phase is of the Ising type.

About the Speaker

Prof. George I. Japaridze received his MSc from the Tbilisi State University in 1975. Starting from 1976, he continuously works at the Andronikashvili Institute of Physics, where he received his PhD degree in 1983 and Doctor of Sciences degree in 1998. Currently he is the head of the Scientific Council of the Institute and Academician-Secretary of the Mathematics and Physics Department of the Georgian National Academy of Sciences. Scientific interests are connected with the physics of low-dimensional systems, including correlated electrons, spin systems, spintronics, theory of metal-insulator transitions, unconventional mechanisms of superconductivity and topological materials.

2019-11-07 10:30 AM
Room: A303 Meeting Room
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