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Title: Exciton diamagnetic shifts and valley Zeeman effects in monolayer WS 2 and MoS 2 to 65 Tesla

In bulk and quantum-confined semiconductors, magneto-optical studies have historically played an essential role in determining the fundamental parameters of excitons (size, binding energy, spin, dimensionality and so on). Here we report low-temperature polarized reflection spectroscopy of atomically thin WS 2 and MoS 2 in high magnetic fields to 65 T. Both the A and B excitons exhibit similar Zeeman splittings of approximately –230 μeV T–1 (g-factor ≃–4), thereby quantifying the valley Zeeman effect in monolayer transition-metal disulphides. Crucially, these large fields also allow observation of the small quadratic diamagnetic shifts of both A and B excitons in monolayer WS 2, from which radii of ~1.53 and ~1.16 nm are calculated. Further, when analysed within a model of non-local dielectric screening, these diamagnetic shifts also constrain estimates of the A and B exciton binding energies (410 and 470 meV, respectively, using a reduced A exciton mass of 0.16 times the free electron mass). Lastly, these results highlight the utility of high magnetic fields for understanding new two-dimensional materials.
Authors:
 [1] ;  [2] ;  [2] ;  [3] ;  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Naval Research Lab., Washington, DC (United States)
  3. Rice Univ., Houston, TX (United States)
Publication Date:
Report Number(s):
LA-UR-15-28855
Journal ID: ISSN 2041-1723; ncomms10643
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 7; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; physical sciences; materials science; condensed matter
OSTI Identifier:
1239580

Stier, Andreas V., McCreary, Kathleen M., Jonker, Berend T., Kono, Junichiro, and Crooker, Scott A.. Exciton diamagnetic shifts and valley Zeeman effects in monolayer WS2 and MoS2 to 65 Tesla. United States: N. p., Web. doi:10.1038/ncomms10643.
Stier, Andreas V., McCreary, Kathleen M., Jonker, Berend T., Kono, Junichiro, & Crooker, Scott A.. Exciton diamagnetic shifts and valley Zeeman effects in monolayer WS2 and MoS2 to 65 Tesla. United States. doi:10.1038/ncomms10643.
Stier, Andreas V., McCreary, Kathleen M., Jonker, Berend T., Kono, Junichiro, and Crooker, Scott A.. 2016. "Exciton diamagnetic shifts and valley Zeeman effects in monolayer WS2 and MoS2 to 65 Tesla". United States. doi:10.1038/ncomms10643. https://www.osti.gov/servlets/purl/1239580.
@article{osti_1239580,
title = {Exciton diamagnetic shifts and valley Zeeman effects in monolayer WS2 and MoS2 to 65 Tesla},
author = {Stier, Andreas V. and McCreary, Kathleen M. and Jonker, Berend T. and Kono, Junichiro and Crooker, Scott A.},
abstractNote = {In bulk and quantum-confined semiconductors, magneto-optical studies have historically played an essential role in determining the fundamental parameters of excitons (size, binding energy, spin, dimensionality and so on). Here we report low-temperature polarized reflection spectroscopy of atomically thin WS2 and MoS2 in high magnetic fields to 65 T. Both the A and B excitons exhibit similar Zeeman splittings of approximately –230 μeV T–1 (g-factor ≃–4), thereby quantifying the valley Zeeman effect in monolayer transition-metal disulphides. Crucially, these large fields also allow observation of the small quadratic diamagnetic shifts of both A and B excitons in monolayer WS2, from which radii of ~1.53 and ~1.16 nm are calculated. Further, when analysed within a model of non-local dielectric screening, these diamagnetic shifts also constrain estimates of the A and B exciton binding energies (410 and 470 meV, respectively, using a reduced A exciton mass of 0.16 times the free electron mass). Lastly, these results highlight the utility of high magnetic fields for understanding new two-dimensional materials.},
doi = {10.1038/ncomms10643},
journal = {Nature Communications},
number = ,
volume = 7,
place = {United States},
year = {2016},
month = {2}
}