Related papers: Valley-Polarized quantum Hall phase in a strain-co…
Quantum Hall physics is at the heart of research on both matter and artificial systems, such as cold atomic gases, with non-trivial topological order. We report on the observation of a chiral edge current by transferring atomic wavepackets…
We show that the Quantum Spin Hall Effect, a state of matter with topological properties distinct from conventional insulators, can be realized in HgTe/CdTe semiconductor quantum wells. By varying the thickness of the quantum well, the…
The quantum spin Hall (QSH) state is a topologically non-trivial state of quantum matter which preserves time-reversal symmetry; it has an energy gap in the bulk, but topologically robust gapless states at the edge. Recently, this novel…
Quantum dots in silicon are promising candidates for implementation of solid-state quantum information processing. It is important to understand the effects of the multiple conduction band valleys of silicon on the properties of these…
Valley, as a degree of freedom, has been exploited to realize valley-selective Hall transport and circular dichroism in two-dimensional layered materials. On the other hand, orbital angular momentum of light with helical phase distribution…
We present a comprehensive theoretical study of strain-engineered quantum transport in monolayer tungsten diselenide (WSe$_2$) in the presence of an electrostatic scalar potential. By incorporating strain effects within a low-energy Dirac…
Developing alternative paradigms of electronics beyond silicon technology requires the exploration of fundamentally new physical mechanisms, such as the valley specific phenomena in hexagonal two-dimensional materials. We realize ballistic…
Bilayer graphene subjected to perpendicular magnetic and electric fields displays a subtle competition between different symmetry broken phases, resulting from an interplay between the internal spin and valley degrees of freedom. The…
Motivated by a recent experiment (Sanchez-Yamagishi et.al, arXiv:1602.06815) reporting evidence of helical spin-polarized edge states in layer-biased twisted bilayer graphene under a magnetic flux, we study the possibility of stabilising a…
Realizing the topological bands of helical states poses a challenge in studying ultracold atomic gases. Motivated by the recent experimental success in realizing chiral optical ladders, here we present a scheme for synthesizing topological…
We measured the magnetoresistance of bilayer quantum Hall (QH) effects at the fractional filling factor $\nu =2/3$ by changing the total electron density and the density difference between two layers. Three different QH states were…
The effects of impurity scattering on a general Abelian fractional quantum Hall (FQH) edge state are analyzed within the chiral-Luttinger-liquid model of low-energy edge dynamics. We find that some disordered edges can have several…
By constructing germanene (silicene, stanene)/$M$Bi$_2$Te$_4$ ($M$ = 3d-transition elements) heterostructures, we discovered and designed multimechanism quantum-anomalous-Hall (QAH) systems, including $\Gamma$-based QAH, $K$-$K'$-connected…
We study the quantum Hall effect of 2D electron gas in black phosphorus in the presence of perpendicular electric and magnetic fields. In the absence of a bias voltage, the external magnetic field leads to a quantization of the energy…
Electron spin-qubits in silicon-germanium (SiGe) heterostructures are a major candidate for the realization of scalable quantum computers. A critical challenge in strained Si/SiGe quantum wells (QWs) is the existence of two nearly…
We theoretically investigate spin-valley-locked tunneling transport in a transition-metal dichalcogenide/ferromagnetic-insulator heterostructure under a perpendicular magnetic field, driven by the spin Seebeck effect. We demonstrate that…
We find that quantum spin Hall (QSH) state can be obtained on a square-like or rectangular lattice, which is generalized from two-dimensional (2D) transition metal dichalcogenide (TMD) haeckelites. Band inversion is shown to be controled by…
We study the quantum valley Hall effect and related domain wall modes in twisted bilayer graphene at a large commensurate angle. Due to the quantum valley and sub-valley Hall effect, a small deviation from the commensurate angle generates…
Motivated by recent transport experiments, we theoretically study the quantum Hall effect in topological semimetal films. Owing to the confinement effect, the bulk subbands originating from the chiral Landau levels establish energy gaps…
Fractional quantum Hall (FQH) effects in graphene are studied because of their relativistic characteristics and the valley degree of freedom. Recently FQH effects have been observed at various filling factors with graphene on a hexagonal…