71 research outputs found
Berry Curvature Engineering by Gating Two-Dimensional Antiferromagnets
Recent advances in tuning electronic, magnetic, and topological properties of
two-dimensional (2D) magnets have opened a new frontier in the study of quantum
physics and promised exciting possibilities for future quantum technologies. In
this study, we find that the dual-gate technology can well tune the electronic
and topological properties of antiferromagnetic (AFM) even septuple-layer (SL)
MnBiTe thin films. Under an out-of-plane electric field that breaks
symmetry, the Berry curvature of the thin film could be
engineered efficiently, resulting in a huge change of anomalous Hall (AH)
signal. Beyond the critical electric field, the double-SL MnBiTe thin
film becomes a Chern insulator with a high Chern number of 3. We further
demonstrate that such 2D material can be used as an AFM switch via
electric-field control of the AH signal. These discoveries inspire the design
of low-power memory prototype for future AFM spintronic applications.Comment: 7 pages, 4 figure
Widely tunable band gap in a multivalley semiconductor SnSe by potassium doping
SnSe, a group IV-VI monochalcogenide with layered crystal structure similar
to black phosphorus, has recently attracted extensive interests due to its
excellent thermoelectric properties and potential device applications.
Experimental electronic structure of both the valence and conduction bands is
critical for understanding the effects of hole versus electron doping on the
thermoelectric properties, and to further reveal possible change of the band
gap upon doping. Here, we report the multivalley valence bands with a large
effective mass on semiconducting SnSe crystals and reveal single-valley
conduction bands through electron doping to provide a complete picture of the
thermoelectric physics. Moreover, by electron doping through potassium
deposition, the band gap of SnSe can be widely tuned from 1.2 eV to 0.4 eV,
providing new opportunities for tunable electronic and optoelectronic devices
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