TY - JOUR
T1 - NaSn2As2
T2 - An Exfoliatable Layered van der Waals Zintl Phase
AU - Arguilla, Maxx Q.
AU - Katoch, Jyoti
AU - Krymowski, Kevin
AU - Cultrara, Nicholas D.
AU - Xu, Jinsong
AU - Xi, Xiaoxiang
AU - Hanks, Amanda
AU - Jiang, Shishi
AU - Ross, Richard D.
AU - Koch, Roland J.
AU - Ulstrup, Søren
AU - Bostwick, Aaron
AU - Jozwiak, Chris
AU - McComb, David W.
AU - Rotenberg, Eli
AU - Shan, Jie
AU - Windl, Wolfgang
AU - Kawakami, Roland K.
AU - Goldberger, Joshua E.
N1 - Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/10/25
Y1 - 2016/10/25
N2 - The discovery of new families of exfoliatable 2D crystals that have diverse sets of electronic, optical, and spin-orbit coupling properties enables the realization of unique physical phenomena in these few-atom-thick building blocks and in proximity to other materials. Herein, using NaSn2As2 as a model system, we demonstrate that layered Zintl phases having the stoichiometry ATt2Pn2 (A = group 1 or 2 element, Tt = group 14 tetrel element, and Pn = group 15 pnictogen element) and feature networks separated by van der Waals gaps can be readily exfoliated with both mechanical and liquid-phase methods. We identified the symmetries of the Raman-active modes of the bulk crystals via polarized Raman spectroscopy. The bulk and mechanically exfoliated NaSn2As2 samples are resistant toward oxidation, with only the top surface oxidizing in ambient conditions over a couple of days, while the liquid-exfoliated samples oxidize much more quickly in ambient conditions. Employing angle-resolved photoemission spectroscopy, density functional theory, and transport on bulk and exfoliated samples, we show that NaSn2As2 is a highly conducting 2D semimetal, with resistivities on the order of 10-6 ω·m. Due to peculiarities in the band structure, the dominating p-type carriers at low temperature are nearly compensated by the opening of n-type conduction channels as temperature increases. This work further expands the family of exfoliatable 2D materials to layered van der Waals Zintl phases, opening up opportunities in electronics and spintronics.
AB - The discovery of new families of exfoliatable 2D crystals that have diverse sets of electronic, optical, and spin-orbit coupling properties enables the realization of unique physical phenomena in these few-atom-thick building blocks and in proximity to other materials. Herein, using NaSn2As2 as a model system, we demonstrate that layered Zintl phases having the stoichiometry ATt2Pn2 (A = group 1 or 2 element, Tt = group 14 tetrel element, and Pn = group 15 pnictogen element) and feature networks separated by van der Waals gaps can be readily exfoliated with both mechanical and liquid-phase methods. We identified the symmetries of the Raman-active modes of the bulk crystals via polarized Raman spectroscopy. The bulk and mechanically exfoliated NaSn2As2 samples are resistant toward oxidation, with only the top surface oxidizing in ambient conditions over a couple of days, while the liquid-exfoliated samples oxidize much more quickly in ambient conditions. Employing angle-resolved photoemission spectroscopy, density functional theory, and transport on bulk and exfoliated samples, we show that NaSn2As2 is a highly conducting 2D semimetal, with resistivities on the order of 10-6 ω·m. Due to peculiarities in the band structure, the dominating p-type carriers at low temperature are nearly compensated by the opening of n-type conduction channels as temperature increases. This work further expands the family of exfoliatable 2D materials to layered van der Waals Zintl phases, opening up opportunities in electronics and spintronics.
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U2 - 10.1021/acsnano.6b04609
DO - 10.1021/acsnano.6b04609
M3 - Article
C2 - 27700035
AN - SCOPUS:84993929579
SN - 1936-0851
VL - 10
SP - 9500
EP - 9508
JO - ACS nano
JF - ACS nano
IS - 10
ER -