2DCC User Research Higlight

Project Summary: Angle-resolved photoemission spectroscopy (ARPES) has been established as a powerful tool to directly reveal electronic band structures of materials and played a critical role in discovering various topological materials such as topological insulators, Dirac semimetals, and Weyl semimetals. Investigations on quantum materials often require the combination of different modalities in photoemission spectroscopy.

Project Summary: Two-dimensional semiconductors have recently emerged as a host material for quantum emitters of single photons. While several reports on defect- and strain-induced single photon emission from 2D chalcogenides exist, a bottom-up, lithography-free approach to producing a high density of emitters has remained elusive.

What Has Been Achieved:

This paper reported a comprehensive study of magnetic proximity effect (MPE) in bilayers that interface a topological insulator (Bi2Se3) with an insulating ferromagnet {MgAl0.5Fe1.5O4), demonstrating the need for careful interpretation of polarized neutron reflectometry and anomalous effect data that are often used to show purported evidence of MPE.

Importance of the Achievement:

What Has Been Achieved:

Design and demonstration of an ultrafast optical modulator operating at near-IR and mid-IR based on a graphene metallic metasurface absorber (GMMA) structure.

Importance of the Achievement:

What Has Been Achieved:

This works demonstrates interlayer magnetophononic coupling in the layered magnetic topological insulator MnBi2Te4

Importance of the Achievement:

The results resulting from this work demonstrates a pathway toward achieving ultrafast light-induced topological phase transitions.

Unique Feature(s) of the MIP that Enabled this Achievement:

What Has Been Achieved:

The formations of charge and lattice orders are generally coupled in charge density wave (CDW) materials. However, this work reveals the presence of a surprising quasi-one-dimensional Fermi surface with nesting condition and find that the wave vectors of the fermi surface nesting and periodic lattice distortion are different, suggesting the decoupled formation between charge and lattice orders.

Importance of the Achievement:

What Has Been Achieved:

A process to produce wafer-scale single-layer amorphous MoO3 was developed by UV-ozone oxidation of a MoS2 monolayer. The ultrathin MoO3 was used an active device layer to demonstrate the thinnest oxide-based nonvolatile resistive switching device that exhibits low voltage operation and high ON/OFF ratio.

Importance of the Achievement:

What Has Been Achieved:

Demonstrate ultrafast optical melting of trimer superstructure in layered 1T′-TaTe2.

Importance of the Achievement:

What Has Been Achieved:

This work successfully fabricated nano-scale crossed junctions composed of two vdW nanowires: p-type Ta2Pt3Se8 (TPtS) and n-type Ta2Pd3Se8 (TPdS) and revealed its unique electronic and optoelectronic properties.

Importance of the Achievement:

This work not only reveals a route to build a nanoscale crossed junction between two quasi-1D vdW materials, but also shed light on the electrical transport and photocurrent generation mechanisms for the nanoscale crossed junctions.