TY - JOUR
T1 - Metal-insulator transition in a semiconductor nanocrystal network
AU - Greenberg, Benjamin L.
AU - Robinson, Zachary L.
AU - Ayino, Yilikal
AU - Held, Jacob T.
AU - Peterson, Timothy A.
AU - Andre Mkhoyan, K.
AU - Pribiag, Vlad S.
AU - Aydil, Eray S.
AU - Kortshagen, Uwe R.
N1 - Funding Information:
We thank L. Francis for providing access to the intense pulse light facilities; P. Crowell for providing access to the Physical Property Measurement System; G. Nelson for assistance with low-intensity UV experiments; J. Garcia Barriocanal for assistance with diffractometry; and B. Shklovskii, M. Sammon, K. Reich, and R. Fernandes for discussions of the data and manuscript. This work was supported primarily by the NSF through the University of Minnesota Materials Research Science and Engineering Center (MRSEC) under award number DMR-1420013. Parts of this work were carried out in the College of Science and Engineering Characterization Facility, University of Minnesota, which has received capital equipment funding from the NSF through the UMN MRSEC program under award number DMR-1420013. Parts of this work were carried out in the College of Science and Engineering Minnesota Nanocenter, University of Minnesota, which receives partial support from the NSF through the National Nanotechnology Infrastructure Network (NNIN) program.
Publisher Copyright:
Copyright © 2019 The Authors,
PY - 2019/8/23
Y1 - 2019/8/23
N2 - Many envisioned applications of semiconductor nanocrystals (NCs), such as thermoelectric generators and transparent conductors, require metallic (nonactivated) charge transport across an NC network. Although encouraging signs of metallic or near-metallic transport have been reported, a thorough demonstration of nonzero conductivity, σ, in the 0 K limit has been elusive. Here, we examine the temperature dependence of σ of ZnO NC networks. Attaining both higher σ and lower temperature than in previous studies of ZnO NCs (
T as low as 50 mK), we observe a clear transition from the variable-range hopping regime to the metallic regime. The critical point of the transition is distinctly marked by an unusual power law close to σ ∝
T
1/5. We analyze the critical conductivity data within a quantum critical scaling framework and estimate the metal-insulator transition (MIT) criterion in terms of the free electron density,
n, and interparticle contact radius, ρ.
AB - Many envisioned applications of semiconductor nanocrystals (NCs), such as thermoelectric generators and transparent conductors, require metallic (nonactivated) charge transport across an NC network. Although encouraging signs of metallic or near-metallic transport have been reported, a thorough demonstration of nonzero conductivity, σ, in the 0 K limit has been elusive. Here, we examine the temperature dependence of σ of ZnO NC networks. Attaining both higher σ and lower temperature than in previous studies of ZnO NCs (
T as low as 50 mK), we observe a clear transition from the variable-range hopping regime to the metallic regime. The critical point of the transition is distinctly marked by an unusual power law close to σ ∝
T
1/5. We analyze the critical conductivity data within a quantum critical scaling framework and estimate the metal-insulator transition (MIT) criterion in terms of the free electron density,
n, and interparticle contact radius, ρ.
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U2 - 10.1126/sciadv.aaw1462
DO - 10.1126/sciadv.aaw1462
M3 - Article
C2 - 31467972
AN - SCOPUS:85071257199
SN - 2375-2548
VL - 5
JO - Science Advances
JF - Science Advances
IS - 8
M1 - eaaw1462
ER -