We investigate the phase diagram of the Haldane-Falicov-Kimball model-a model combining topology, interactions, and spontaneous disorder at finite temperatures. Using an unbiased numerical method, we map out the phase diagram on the interaction-temperature plane. Along with known phases, we unveil an insulating charge ordered state with gapless excitations and a temperature-driven gapless topological insulating phase. Intrinsic-temperature-generated-disorder is the key ingredient explaining the unexpected behavior. Our findings support the possibility of having temperature-driven topological transitions into gapped and gapless topological insulating phases in mass unbalanced systems with two fermionic species.
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http://dx.doi.org/10.1103/PhysRevLett.122.126601 | DOI Listing |
J Phys Condens Matter
January 2025
School of Physical Sciences, NISER, Jatni, Bhubaneswar, 752050, INDIA.
We study topological charge pumping (TCP) in the Rice-Mele (RM) model with irreciprocal hopping. The non-Hermiticity gives rise to interesting pumping physics, owing to the presence of skin effect and exceptional points. In the static one-dimensional (1D) RM model, we find two independent tuning knobs that can drive the topological transition, namely, non-Hermitian parameter $\gamma$ and system size $N$.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
Ultrafast photoexcitation offers a novel approach to manipulating quantum materials. One of the long-standing goals in this field is to achieve optical control over topological properties. However, the impact on their electronic structures, which host gapless surface states, has yet to be directly observed.
View Article and Find Full Text PDFPhys Chem Chem Phys
December 2024
Guizhou Provincial Key Laboratory of Computing and Network Convergence, School of Information, Guizhou University of Finance and Economics, Guiyang 550025, People's Republic of China.
The quantum spin Hall (QSH) effect has attracted extensive research interest due to its great promise in topological quantum computing and novel low-energy electronic devices. Here, using first-principles calculations, we find that MX (M = Ru and Os; X = As and Sb) monolayers are 2D topological insulators (TIs). The spin-orbit coupling (SOC) band gaps for RuAs, RuSb, OsAs, and OsSb monolayers are predicted to be 80, 131, 118, and 221 meV, respectively.
View Article and Find Full Text PDFPhys Rev Lett
November 2024
Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
In the presence of an external magnetic field, the Kitaev model could host either gapped topological anyons or gapless Majorana fermions. In α-RuCl_{3}, the gapped and gapless cases are only separated by a 30° rotation of the in-plane magnetic field vector. The presence or absence of the spectral gap is key for understanding the thermal transport behavior in α-RuCl_{3}.
View Article and Find Full Text PDFJ Phys Condens Matter
December 2024
College of Physics Science and Technology, Yangzhou University, Yangzhou 225002, People's Republic of China.
To investigate the influence of nanoholes on Chern insulators (CIs), we propose a porous Haldane model that considers the nearest-neighbor (NN) hoppings and next-NN (NNN) hoppings with staggered magnetic fluxes. This model supports multiple topological phases with different filling factors. At 2/5 filling, CI phases withC=±1, = 2,C=±3,C=±4and higher-order topological insulator (HOTI) appear.
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