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We investigate the interaction between the counter-rotating bicircular field and the trivial and topological insulator with anomalous Hall conductivity (AHC) to show the effect of the asymmetric spin band and topological invariant. We show that the reaction of the system to the counter-rotating bicircular field is classified into the high-field and low-field regimes. In the high-field regime, it is shown that the AHC of the system is controlled by the phase difference between the ω and 2ω fields. We also show that in the low-field regime, the AHC of the topological insulator is determined by the helicity of the laser, while the AHC is negligible in the trivial insulator. For the spin-orbit coupling (SOC), it is demonstrated that the high SOC increases the required field amplitude for the transition from the low-field to the high-field regime. Also, we show that strong SOC leads to an additional sign change of the AHC in the high-field regime, but with different origins in the trivial and topological insulator.
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http://dx.doi.org/10.1364/OE.501231 | DOI Listing |
Nat Nanotechnol
September 2025
Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA, USA.
Topological photonics explores photonic systems that exhibit robustness against defects and disorder, enabled by protection from underlying topological phases. These phases are typically realized in linear optical systems and characterized by their intrinsic photonic band structures. Here we experimentally study Floquet Chern insulators in periodically driven nonlinear photonic crystals, where the topological phase is controlled by the polarization and the frequency of the driving field.
View Article and Find Full Text PDFACS Nano
September 2025
Hefei National Research Center for Physical Sciences at the Microscale, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
As a versatile platform for exploring exotic quantum phases, moiré superlattices, ranging from twisted graphene to twisted transition metal dichalcogenides, have been intensively studied. In this work, based on exact diagonalization and Hartree-Fock mean-field calculations, the interaction-driven topological phases are investigated in hole-doped twisted bilayer MoS at the high filling factor = 3. Besides the nematic insulator and quantum anomalous Hall phases, the topological Wigner molecule crystal (TWMC) phase is found in the phase diagram.
View Article and Find Full Text PDFACS Nano
September 2025
School of Physics and Astronomy, Monash University, Clayton, VIC 3800, Australia.
Strong electron-hole interactions in a semimetal or narrow-gap semiconductor may drive a ground state of condensed excitons. Monolayer WTe has been proposed as a host material for such an exciton condensate, but the order parameter─the key signature of a macroscopic quantum-coherent condensate─has not been observed. Here, we use Fourier-transform scanning tunneling spectroscopy (FT-STS) to study quasiparticle interference (QPI) and periodic modulations of the local density of states (LDOS) in monolayer WTe.
View Article and Find Full Text PDFJ Phys Chem Lett
September 2025
School of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing 100872, China.
The interplay between topology and magnetism induces various exotic quantum phenomena, with magnetic topological insulators (MTIs) serving as a prominent example due to their ability to host the quantum anomalous Hall effect (QAHE). However, the realization of the QAHE at a higher temperature approaching the magnetic transition temperature remains a significant challenge, primarily due to the scarcity of suitable material platforms and our limited understanding of the intricate relationships among band topology, magnetism, and defects. Here, we report a comprehensive investigation of MnSbTe·(SbTe) ( = 0-5) single crystals, including the discovery of the novel MnSbTe pure phase.
View Article and Find Full Text PDFJ Phys Condens Matter
September 2025
physics, Jundi-Shapur University of Technology, Dezful, Dezful, 64615/334, Iran (the Islamic Republic of).
We develop a novel framework to study quantum phase transitions in two-dimensional topological insulators (TIs) driven by strain-induced perturbations. Using a new perturbation Hamiltonian that couples mechanical strain to topological edge states, we derive formulations for the continuous transition from topological to trivial insulator phases via an intermediate critical phase. Our model introduces critical exponents (v = 1, z = 1), a universal scaling law for the energy gap, and a real-space correlation function, validated through analytical and numerical methods.
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