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Phase diagram of three fermionic chains: A renormalization‐group study
Author(s) -
Arrigoni E.
Publication year - 1996
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221950211
Subject(s) - phase diagram , renormalization group , physics , hamiltonian (control theory) , condensed matter physics , density matrix renormalization group , transverse plane , phase boundary , quantum mechanics , mathematical physics , phase (matter) , mathematics , mathematical optimization , structural engineering , engineering
The weak‐coupling phase diagram of a system of three coupled spin 1/2 chains (at zero temperature) is studied as a function of fermion density and of transverse single‐particle hopping by means of a renormalization‐group analysis. We identify different phases with a different behavior of the renormalization‐group flow and interpret the effect of relevant couplings in terms of the associated bosonized Hamiltonian. A frustrated (gapped) magnetic spectrum in a large region about and at half filling is obtained in the unphysical case of periodic boundary conditions in the direction transverse to the chains. The expected spin phase diagram (as also observed in the Sr 2 Cu 3 O 5 ladder compounds) is instead obtained when open transverse boundary conditions are considered. In particular, the spin modes are ungapped in a wide region about half filling and at half filling down to a critical value of the transverse hopping t⟂. A Mott transition as a function of ⟂ is thus present at half filling.