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It is known that cuprate artificial high Tc superlattices (AHTS) with period d, composed of quantum wells confining interface space charge in stoichiometric Mott insulator layers (S), with thickness L, at the interface with overdoped normal…

Topological insulators are a novel class of quantum matter with a gapped insulating bulk yet gapless spin helical Dirac fermion conducting surface states. Here, we report local and non-local electrical and magneto transport measurements in…

Mesoscale and Nanoscale Physics · Physics 2016-05-11 Yang Xu , Ireneusz Miotkowski , Yong P. Chen

We have experimentally realized novel space-time inversion (P-T) invariant Z2-type topological semimetal-bands, via an analogy between the momentum space and a controllable parameter space in superconducting quantum circuits. By measuring…

Quantum Physics · Physics 2017-11-03 Xinsheng Tan , Yuxin Zhao , Qiang Liu , Guangming Xue , Haifeng Yu , Zidan Wang , Yang Yu

We present unconventional nodal crossings in a two-dimensional (2D) collinear altermagnet, which are enforced by crystal symmetries to lock spin polarization and valley degrees of freedom. The altermagnetism generate nonrelativistic…

Mesoscale and Nanoscale Physics · Physics 2025-11-04 Zhang Meng-Han , Guo Xuan , Dao-Xin Yao

Recent experimental investigations of arrays of magnetic atoms deposited on top of a superconductor have opened a new chapter in the search of topological superconductivity. We generalize the microscopic model derived by Pientka et al.…

Mesoscale and Nanoscale Physics · Physics 2015-06-22 Joel Röntynen , Teemu Ojanen

This paper discusses the properties of flexural waves obeying the biharmonic equation, propagating in a thin plate pinned at doubly-periodic sets of points. The emphases are on the properties of dispersion surfaces having the Dirac cone…

Mathematical Physics · Physics 2015-08-19 R. C. McPhedran , A. B. Movchan , N. V. Movchan , M. Brun , M. J. A. Smith

We investigated the properties of dichroic cholesteric liquid crystals (CLCs) being in external static magnetic field directed along helix axis. We have shown that in the case of the wavelength dependence of magneto-optic activity…

Optics · Physics 2023-05-17 A. H. Gevorgyan

We report calculations of the electronic structure of silicene and the stability of its weakly buckled honeycomb lattice in an external electric field oriented perpendicular to the monolayer of Si atoms. We find that the electric field…

Mesoscale and Nanoscale Physics · Physics 2012-02-23 N. D. Drummond , V. Zolyomi , V. I. Fal'ko

We introduce higher-order topological Dirac superconductor (HOTDSC) as a new gapless topological phase of matter in three dimensions, which extends the notion of Dirac phase to a higher-order topological version. Topologically distinct from…

Mesoscale and Nanoscale Physics · Physics 2020-12-07 Rui-Xing Zhang , Yi-Ting Hsu , S. Das Sarma

Silicene is a monolayer of silicon atoms forming a two-dimensional honeycomb lattice. We investigate the topological properties of a silicene superstructure generated by an external periodic potential. The superstructure is a quantum…

Mesoscale and Nanoscale Physics · Physics 2013-04-12 Motohiko Ezawa

The robustness of quantum edge transport in InAs/GaSb quantum wells in the presence of magnetic fields raises an issue on the fate of topological phases of matter under time-reversal symmetry breaking. A peculiar band structure evolution in…

Mesoscale and Nanoscale Physics · Physics 2018-01-23 Chang-An Li , Song-Bo Zhang , Shun-Qing Shen

We explore the emergence of spin-polarised flat-bands at head-to-head domain walls in a recently predicted class of antiferromagnetic topological insulators hosting planar magnetisation. We show, in the framework of quantum well physics,…

Mesoscale and Nanoscale Physics · Physics 2021-09-01 N. B. Devlin , T. Ferrus , C. H. W. Barnes

While the search of high Tc superconductivity was driven mostly by trial and error methodology searching for novel materials, here we provide a quasi-first-principle quantum theory for engineering superconductivity in artificial high-Tc…

Superconductivity · Physics 2024-11-19 Antonio Valletta , Antonio Bianconi , Andrea Perali , Gennady Logvenov , Gaetano Campi

Based on first-principles calculations we showed that superlattices of periodically repeated junctions of hydrogen saturated silicon nanowire segments having different lengths and diameters form multiple quantum well structures. The band…

Mesoscale and Nanoscale Physics · Physics 2010-12-22 Seymur Cahangirov , Salim Ciraci

The recent discovery of Dirac semimetals represents a new achievement in our fundamental understanding of topological states of matter. Due to their topological surface states, high mobility, and exotic properties associated with bulk Dirac…

Mesoscale and Nanoscale Physics · Physics 2015-02-13 Xianbo Xiao , Shengyuan A. Yang , Zhengfang Liu , Huili Li , Guanghui Zhou

We theoretically predict two new classes of three-dimensional topological crystalline insulators (TCIs), which have an odd number of unpinned surface Dirac cones protected by crystal symmetries. The first class is protected by a single…

Mesoscale and Nanoscale Physics · Physics 2015-04-16 Chen Fang , Liang Fu

We prepare a gate-defined quadruple quantum dot to study the gate-tunability of single to quadruple quantum dots with finite inter-dot tunnel couplings. The measured charging energies of various double dots suggest that the dot size is…

Mesoscale and Nanoscale Physics · Physics 2014-03-21 Tatsuki Takakura , Akito Noiri , Toshiaki Obata , Tomohiro Otsuka , Jun Yoneda , Katsuharu Yoshida , Seigo Tarucha

We employed first-principles density-functional theory (DFT) calculations to characterize Dirac electrons in quasi-two-dimensional molecular conductor $\alpha$-(BETS)$_2$I$_3$ [= $\alpha$-(BEDT-TSeF)$_2$I$_3$] at a low temperature of 30K.…

Strongly Correlated Electrons · Physics 2021-01-18 Takao Tsumuraya , Yoshikazu Suzumura

Owing to their chiral cubic structure, exotic multifold topological excitations have been predicted and recently observed in transition metal silicides like $\beta$-RhSi. Herein, we report that the topological character of RhSi is also…

We study theoretically two-dimensional single-crystalline sheets of semiconductors that form a honeycomb lattice with a period below 10 nm. These systems could combine the usual semiconductor properties with Dirac bands. Using atomistic…

Mesoscale and Nanoscale Physics · Physics 2015-02-19 E. Kalesaki , C. Delerue , C. Morais Smith , W. Beugeling , G. Allan , D. Vanmaekelbergh