Field Induced Chiral Soliton Phase in the Kitaev Spin Chain

Abstract

The bond-dependent Ising interaction present in the Kitaev model has attracted considerable attention. The appearance of an unexpected intermediate phase under a magnetic field is particularly intriguing, and one may wonder if a similar phase occurs in the Kitaev spin chain with alternating $x$- and $y$-bond Ising interactions. Previous studies have focused on a transverse field, $h_z$, and reported a direct transition to the polarized state. Here, we investigate phases with arbitrary angle of two longitudinal fields, $h_x$ and $h_y$. For a magnetic field applied along the diagonal, $h_x$=$h_y$, the chain remains gapless up to a critical field $h_{xy}^{c_1}$. Surprisingly, above $h_{xy}^{c1}$ it enters an unusual intermediate phase before reaching the polarized state at $h_{xy}^{c_2}$. This phase is characterized by a staggered vector chirality and for periodic boundary conditions, a two-fold degeneracy with a finite gap. For open boundary systems the ground-state exhibits a single soliton, lowering the energy, and gapless excitations. However, the corresponding anti-soliton raises the energy sufficiently that a gap appears for soliton and anti-soliton pairs in periodic systems. An intuitive variational picture is developed describing the soliton phase.

6 pages, 5 figures

References in corpus (5)

• The density-matrix renormalization group in the age of matrix product states
• Topological characterization of quantum phase transitions in a S=1/2 spin model
• Ground-state phase diagram of a spin-1/2 frustrated ferromagnetic XXZ chain: Haldane dimer phase and gapped/gapless chiral phases
• Quantum Fluctuations of Chirality in One-Dimensional Spin-1/2 Multiferroics: Gapless Dielectric Response from Phasons and Chiral Solitons
• Nonsymmorphic chiral symmetry and solitons in the Rice-Mele model

Cited by in corpus (11)

• Beyond Kitaev physics in strong spin-orbit coupled magnets
• Spin dynamics of the generalized quantum spin compass chain
• Spontaneous dimerization, spin-nematic order, and deconfined quantum critical point in a spin-1 Kitaev chain with tunable single-ion anisotropy
• Islands of Chiral Solitons in Integer Spin Kitaev Chains
• Twice Hidden String Order and Competing Phases in the Spin-1/2 Kitaev-Gamma Ladder
• Left-left-right-right magnetic order in spin-1/2 Kitaev-Heisenberg chain
• Dimensional reduction of Kitaev spin liquid at quantum criticality
• The spin-orbital Kitaev model: from kagome spin ice to classical fractons
• Exact Ground States and Phase Diagram of the Quantum Compass Model under an in-plane Field
• Field-Induced Ordered Phases in Anisotropic Spin-1/2 Kitaev Chains
• Emergent dipole field theory in atomic ladders