Field‐Controlled Luttinger Liquid and Possible Crossover into Spin Liquid in Strong‐Rail Ladder Systems

Abstract

The thermodynamics and transport properties of strong-rail ladder systems are investigated by means of Green's function theory. It is shown that the magnetic behavior clearly manifests a typical antiferromagnetism with gapped or gapless low-lying excitations, which is in agreement with the experimental results. In addition, the temperature-field-induced phase diagram is explored, and we demonstrate a Luttinger liquid behavior in the window h(c) (marking the ending of the M=0 plateau)<h<h(s) (saturation magnetic field) within a narrow range of temperature. The spin liquid phase is uncovered for h<h(c) upon cooling down to zero temperature. It is also shown that the rung entanglement entropy is a good indicator for detecting the field-driven quantum criticality. Meanwhile, the magnetic susceptibility, the specific heat, and the thermal (spin) Drude weights are calculated to characterize the plentiful quantum phases, in which the thermal insulating and conducting behaviors can be controlled by magnetic fields.

Bose-Einstein condensation in quantum magnets

“…IV). Magnets that reproduce bosonic gases with attractive interactions can also be used for observing Efimov states (Efimov, 1970;Nishida, Kato, and Batista, 2013). Spin-supersolid states are also predicted to appear for bipartite lattices of S ¼ 1 dimers (Sengupta and Batista, 2007a).…”

“…The Luttinger liquid is the most ubiquitous gapless phase of onedimensional systems (Sachdev, 1994;Giamarchi and Tsvelik, 1999;Ding, Yao, and Fu, 2010;Cazalilla et al, 2011;Crépin et al, 2011;Ninios et al, 2012). It can be reached in quantum magnets, for example, by closing the Haldane gap in a 1D Haldane chain with applied magnetic fields, or the spin gap in a 1D spin ladder.…”

Ferrimagnetism induced by asymmetrical ferromagnetic next-nearest-neighbour exchange interactions in an antiferromagnetic spin-1/2 zigzag chain

“…On the contrary, as the asymmetry degree of the FM NNN exchange interactions decreases, the low-temperature sharp peak and the minimum in the χT curve are both suppressed, implying that the χT curve of the magnetic system approaches the AFM one, which was clearly observed in AFM spin ladder systems. [28] Accordingly, the asymmetrical FM NNN exchange interaction plays a crucial role for the occurrence of the ferrimagnetic ordering in the AFM spin-1/2 zigzag chain. It is also instructive to investigate the appearance of the ferrimagnetic ordering by tracing the change of the elementary excitation spectra for the AFM spin-1/2 zigzag chains with the symmetrical and the asymmetrical NNN exchange interactions (see Fig.…”