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Condensed Matter Seminar - Feng Miao

Feng Miao - Nanjing University

Tuesday, August 22, 2017
  4–5:20 p.m.


Location: Physics Building Reading Room
  Parking Information

Category: Seminar

Description:

Electronic Transport and Device Applications of 2D Materials


During the last decade, tremendous research efforts have been focused on two-dimensional (2D) materials due to their rich physics and potentials for many applications. In this talk, I will mainly discuss our recent studies on transition-metal dichalcogenides (TMDs) with low lattice symmetry. The first part of the talk will focus on a predicted type-II Weyl semimetal (WSM) material, tungsten ditelluride (WTe2). We observed notable angle-sensitive negative longitudinal magnetoresistance (MR) and strong planar orientation dependence which reveal important transport signatures of chiral anomaly. By applying a gate voltage, we further demonstrated that the Fermi energy can be tuned through the Weyl points via the electric field effect; this is the first report of controlling the unique transport properties in situ in a WSM system. [1]


The second part of the talk will cover our studies on atomically thin rhenium disulfide (ReS2) flakes with interesting in-plane anisotropic transport and mechanical properties, as well as excellent optoelectronic properties. We fabricated mono- and few-layer ReS2 field effect transistors (FET), which exhibit competitive FET performances and record-high anisotropic ratio. We further successfully demonstrated an integrated digital inverter with high gain by utilizing two ReS2 anisotropic FETs, suggesting the promising implementation of large-scale 2D logic circuits. [2] Our latest results on high-performance photodetectors based on atomically thin van der Waals (vdW) heterostructures (made of TMDs、black arsenic phosphorus or graphene) will also be presented. [3-5]


References:


[1] Wang, et al. “Gate-Tunable Negative Longitudinal Magnetoresistance in the Predicted Type-II Weyl Semimetal WTe2”, Nat. Comm. 7, 13142 (2016). [2] Liu, et al. “Integrated Digital Inverters Based on Two-dimensional Anisotropic ReS2 Field-effect Transistors”, Nat. Comm. 6, 6991 (2015). [3] Long, et al. “Room-temperature high detectivity mid-infrared photodetectors based on black arsenic phosphorus”, Science Adv. 3, e1700589 (2017).  [4] Long, et al. “Broadband photovoltaic detectors based on an atomically thin heterostructure”, Nano Lett. 16, 2254 (2016). [5] Liu, et al. “Ultra-high responsivity phototransistors based on few-layer ReS2 for weak signal detection”, Adv. Func. Mater. 26, 1938 (2016).




Additional Information: Colloquia & Seminars

Open to: General Public
Admission: Free
Sponsor: Physics and Astronomy

Contact Information:
Naveen Reddy
951-827-3492
naveen.reddy@ucr.edu