Current browse context:
cond-mat.str-el
Change to browse by:
References & Citations
Condensed Matter > Strongly Correlated Electrons
Title: Unusual excitations and double-peak specific heat in a bond-alternating spin-$1$ $K$-$Γ$ chain
(Submitted on 21 Apr 2021 (v1), last revised 13 Jul 2021 (this version, v2))
Abstract: One-dimensional gapped phases that avoid any symmetry breaking have drawn enduring attention. In this paper, we study such phases in a bond-alternating spin-1 $K$-$\Gamma$ chain built of a Kitaev ($K$) interaction and an off-diagonal $\Gamma$ term. In the case of isotropic bond strength, a Haldane phase, which resembles the ground state of a spin-$1$ Heisenberg chain, is identified in a wide region. A gapped Kitaev phase situated at dominant ferromagnetic and antiferromagnetic Kitaev limits is also found. The Kitaev phase has extremely short-range spin correlations and is characterized by finite $\mathbb{Z}_2$-valued quantities on bonds. Its lowest entanglement spectrum is unique, in contrast to the Haldane phase whose entanglement spectrum is doubly degenerate. In addition, the Kitaev phase shows a double-peak structure in the specific heat at two different temperatures. In the pure Kitaev limit, the two peaks are representative of the development of short-range spin correlation at $T_h \simeq 0.5680$ and the freezing of $\mathbb{Z}_2$ quantities at $T_l \simeq 0.0562$, respectively. By considering bond anisotropy, regions of Haldane phase and Kitaev phase are enlarged, accompanied by the emergence of dimerized phases and three distinct magnetically ordered states.
Submission history
From: Qiang Luo [view email][v1] Wed, 21 Apr 2021 19:04:06 GMT (899kb,D)
[v2] Tue, 13 Jul 2021 22:12:34 GMT (895kb,D)
Link back to: arXiv, form interface, contact.