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Related papers: Chiral valley phonons and flat phonon bands in moi…

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According to electronic structure theory, bilayer graphene is expected to have anomalous electronic properties when it has long-period moir\'e patterns produced by small misalignments between its individual layer honeycomb lattices. We have…

We have studied the S=1/2 quasi-one-dimensional antiferromagnet TiOCl using single crystal x-ray diffraction and inelastic x-ray scattering techniques. The Ti ions form staggered spin chains which dimerize below Tc1 = 66 K and have an…

Strongly Correlated Electrons · Physics 2009-11-13 E. T. Abel , K. Matan , F. C. Chou , E. D. Isaacs , D. E. Moncton , H. Sinn , A. Alatas , Y. S. Lee

We report the experimental observation of the spin-wave moir\'e edge and cavity modes using Brillouin light scattering spectro-microscopy in a nanostructured magnetic moir\'e lattice consisting of two twisted triangle antidot lattices based…

Motivated by recent observation of the quantum spin Hall effect in monolayer germanene and twisted bilayer transition-metal-dichalcogenides (TMDs), we study the topological phases of moir\'e twisted bilayers with time-reversal symmetry and…

Mesoscale and Nanoscale Physics · Physics 2024-05-24 Yi-Ming Wu , Daniel Shaffer , Zhengzhi Wu , Luiz H. Santos

The selective excitation of coherent phonons provides unique capabilities to control fundamental properties of quantum materials on ultrafast time scales. For instance, in the presence of strong electron-phonon coupling, the electronic band…

Materials Science · Physics 2020-06-02 P. Hein , S. Jauernik , H. Erk , L. Yang , Y. Qi , Y. Sun , C. Felser , M. Bauer

The concept of chirality makes ubiquitous appearance in nature. Particularly, both a structure and its collective excitations may acquire well defined chiralities. In this work, we reveal an intrinsic connection between the chiralities of a…

Materials Science · Physics 2024-05-21 Hao Chen , Weikang Wu , Jiaojiao Zhu , Weikang Gong , Weibo Gao , Shengyuan A. Yang , Lifa Zhang

Advances in material fabrication techniques and growth methods have opened up a new chapter for twistronics, in the form of twisted freestanding three-dimensional material membranes. Through first-principles calculations based on density…

Materials Science · Physics 2025-06-06 Seungjun Lee , D. J. P. de Sousa , Bharat Jalan , Tony Low

We investigate the moir\'e band structures and the strong correlation effects in twisted bilayer MoTe$_2$ for a wide range of twist angles, employing a combination of various techniques. Using large-scale first principles calculations, we…

Strongly Correlated Electrons · Physics 2024-03-04 Cheng Xu , Jiangxu Li , Yong Xu , Zhen Bi , Yang Zhang

We show how to include the Jahn-Teller coupling of \mo phonons to the electrons in the continuum model formalism which describes small-angle twisted bilayer graphene. These phonons, which strongly couple to the valley degree of freedom, are…

Superconductivity · Physics 2020-07-03 M. Angeli , M. Fabrizio

There has been remarkable recent progress in the formation of nano-resonators that support ultra-low-loss, compact dielectric photonic crystals with exceptional high-Q modes that operate at visible or telecom wavelengths. New insights into…

Optics · Physics 2022-12-21 Haoning Tang , Xueqi Ni , Fan Du , Eric Mazur

We construct a phenomenological scattering theory for the triangular network of valley Hall states that arises in twisted bilayer graphene under interlayer bias. Crucially, our network model includes scattering between different valley Hall…

Mesoscale and Nanoscale Physics · Physics 2020-09-02 C. De Beule , F. Dominguez , P. Recher

Spatially indirect excitons with displaced wavefunctions of electrons and holes play a pivotal role in a large portfolio of fascinating physical phenomena and emerging optoelectronic applications, such as valleytronics, exciton spin Hall…

Using femtosecond time-resolved X-ray diffraction, we investigated optically excited coherent acoustic phonons in the Weyl semimetal TaAs. The low symmetry of the (112) surface probed in our experiment enables the simultaneous excitation of…

Chirality is a fundamental concept in physics that underpins various phenomena in nonlinear optics, quantum physics, and topological photonics. Although the spin of a photon naturally brings chirality, orbital angular momentum can also…

Chiral phonons, circularly polarized lattice vibrations carrying intrinsic angular momentum, offer unprecedented opportunities for controlling heat flow, manipulating quantum states through spin-phonon coupling, and realizing exotic…

Two-dimensional (2D) materials may host circular phonons, considered as chiral if the presence of a substrate breaks mirror symmetry. In 2D transition metal dichalcogenide (TMDC) monolayers lacking inversion symmetry, phonons with a given…

Materials Science · Physics 2025-09-16 Banhi Chatterjee , Peter Kratzer

In this paper, the chiral Hall effect of strained Weyl semimetals without any external magnetic field is proposed. Electron-phonon coupling emerges in the low-energy fermionic sector through a pseudogauge potential. We show that, by using…

Materials Science · Physics 2020-04-22 Shiva Heidari , Reza Asgari

Moir\'e materials with flat electronic bands provide a highly controllable quantum system for studies of strong-correlation physics and topology. In particular, angle-aligned heterobilayers of semiconducting transition metal dichalcogenides…

Strongly Correlated Electrons · Physics 2022-10-05 Yang Xu , Kaifei Kang , Kenji Watanabe , Takashi Taniguchi , Kin Fai Mak , Jie Shan

We have surveyed the in-plane transport properties of the graphene twist bilayer using (i) a low-energy effective Hamiltonian for the underlying electronic structure, (ii) an isotropic elastic phonon model, and (iii) the linear Boltzmann…

Mesoscale and Nanoscale Physics · Physics 2016-12-21 N. Ray , M. Fleischmann , D. Weckbecker , S. Sharma , O. Pankratov , S. Shallcross

The creation of moir\'e superlattices in twisted bilayers of two-dimensional crystals has been utilised to engineer quantum material properties in graphene and transition metal dichalcogenide (TMD) semiconductors. Here, we examine the…

Mesoscale and Nanoscale Physics · Physics 2024-05-27 J. G. McHugh , V. V. Enaldiev , V. I. Fal'ko