Binghai Yan

Negative magnetoresistance without well-defined chirality in the Weyl semimetal TaP

Weyl semimetals (WSMs) are topological quantum states wherein the electronic bands disperse linearly around pairs of nodes with fixed chirality, the Weyl points. In WSMs, nonorthogonal electric and magnetic fields induce an exotic phenomenon known as the chiral anomaly, resulting in an unconventional negative longitudinal magnetoresistance, the chiral-magnetic effect. However, it remains an open question to which extent this effect survives when chirality is not well-defined. Here, we establish the detailed Fermi-surface topology of the recently identified WSM TaP via combined angle-resolved quantum-oscillation spectra and band-structure calculations. The Fermi surface forms banana-shaped electron and hole pockets surrounding pairs of Weyl points. Although this means that chirality is ill-defined in TaP, we observe a large negative longitudinal magnetoresistance. We show that the magnetoresistance can be affected by a magnetic field-induced inhomogeneous current distribution inside the sample.

Topological states on the gold surface

Gold surfaces host special electronic states that have been understood as a prototype of Shockley surface states. These surface states are commonly employed to benchmark the capability of angle-resolved photoemission spectroscopy (ARPES) and scanning tunnelling spectroscopy. Here we show that these Shockley surface states can be reinterpreted as topologically derived surface states (TDSSs) of a topological insulator (TI), a recently discovered quantum state. Based on band structure calculations, the Z2-type invariants of gold can be well-defined to characterize a TI. Further, our ARPES measurement validates TDSSs by detecting the dispersion of unoccupied surface states. The same TDSSs are also recognized on surfaces of other well-known noble metals (for example, silver, copper, platinum and palladium), which shines a new light on these long-known surface states.

Prediction of Weyl semimetal in orthorhombic MoTe2

We investigate the orthorhombic phase

Oscillatory crossover from two-dimensional to three-dimensional topological insulators

({T}_{d})

Weyl Semimetals as Hydrogen Evolution Catalysts

of the layered transition-metal dichalcogenide

Superconductivity in Weyl semimetal candidate MoTe2

{\mathrm{MoTe}}_{2}

Linear magnetoresistance caused by mobility fluctuations in n-doped Cd3As2

as a Weyl semimetal candidate.

Extremely high magnetoresistance and conductivity in the type-II Weyl semimetals WP2 and MoP2

{\mathrm{MoTe}}_{2}

Single Dirac Cone Topological Surface State and Unusual Thermoelectric Property of Compounds from a New Topological Insulator Family

exhibits four pairs of Weyl points lying slightly above

Topological Materials: Weyl Semimetals

(\ensuremath{\sim}6\phantom{\rule{0.16em}{0ex}}\mathrm{meV})