arXiv subjects

Wei Niu

Publications and source records attributed to Wei Niu.

93 records · Page 6Linked to original sources

arXiv2018

Topological Phase Transition-Induced Tri-Axial Vector Magnetoresistance in (Bi1-xInx)2Se3 Nanodevices

We report the study of a tri-axial vector magnetoresistance (MR) in nonmagnetic (Bi1-xInx)2Se3 nanodevices at the composition of x = 0.08. We show a dumbbell-shaped in-plane negative MR up to room temperature as well as a large out-of-plane positive MR. MR at three directions is about in a -3%: -1%: 225% ratio at 2 K. Through both the thickness and composition-dependent magnetotransport measurements, we show that the in-plane negative MR is due to the topological phase transition enhanced intersurface coupling near the topological critical point. Our devices suggest the great potential for room-temperature spintronic applications, for example, vector magnetic sensors.

physics.app-ph↗

arXiv2016

Unsaturated magnetoconductance of epitaxial La0.7Sr0.3MnO3 thin films in pulsed magnetic fields up to 60 T

We report on the temperature and field dependence of resistance of La0.7Sr0.3MnO3 thin films over a wide temperature range and in pulsed magnetic fields up to 60 T. The epitaxial La0.7Sr0.3MnO3 thin films were deposited by laser molecular beam epitaxy. High magnetic field magnetoresistance curves were fitted by the Brillouin function, which indicated the existence of magnetically polarized regions and the underlying hopping mechanism. The unsaturated magnetoconductance was the most striking finding observed in pulsed magnetic fields up to 60 T. These observations can deepen the fundamental understanding of the colossal magnetoresistance in manganites with strong correlation of transport properties and magnetic ordering.

cond-mat.str-el↗

arXiv2016

Evidence of both surface and bulk Dirac bands in ZrSiS and the unconventional magnetoresistance

The unconventional magnetoresistance of ZrSiS single crystals is found unsaturated till the magnetic field of 53 T with the butterfly shaped angular dependence. Intense Shubnikov-de Haas oscillations resolve a bulk Dirac cone with a nontrivial Berry phase, where the Fermi surface area is 1.80*10^-3 Å-2 and reaches the quantum limit before 20 T. Angle resolved photoemission spectroscopy measurement reveals an electronic state with the two-dimensional nature around the X point of Brillouin zone boundary. By integrating the density functional theory calculations, ZrSiS is suggested to be a Dirac material with both surface and bulk Dirac bands.

cond-mat.mtrl-sci↗