DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Proximity-enhanced valley Zeeman splitting at the WS2/graphene interface

Abstract

The valley Zeeman physics of excitons in monolayer transition metal dichalcogenides provides valuable insight into the spin and orbital degrees of freedom inherent to these materials. Being atomically-thin materials, these degrees of freedom can be influenced by the presence of adjacent layers, due to proximity interactions that arise from wave function overlap across the 2D interface. Here, we report 60 T magnetoreflection spectroscopy of the A- and B- excitons in monolayer WS2, systematically encapsulated in monolayer graphene. While the observed variations of the valley Zeeman effect for the A- exciton are qualitatively in accord with expectations from the bandgap reduction and modification of the exciton binding energy due to the graphene-induced dielectric screening, the valley Zeeman effect for the B- exciton behaves markedly different. We investigate prototypical WS2/graphene stacks employing first-principles calculations and find that the lower conduction band of WS2 at the K / K valleys (the <:tex-math> C B band) is strongly influenced by the graphene layer on the orbital level. Specifically, our detailed microscopicmore » analysis reveals that the conduction band at the Q point of WS2 mediates the coupling between C B and graphene due to resonant energy conditions and strong coupling to the Dirac cone. This leads to variations in the valley Zeeman physics of the B- exciton, consistent with the experimental observations. Our results therefore expand the consequences of proximity effects in multilayer semiconductor stacks, showing that wave function hybridization can be a multi-step energetically resonant process, with different bands mediating the interlayer interactions. Such effects can be further exploited to resonantly engineer the spin-valley degrees of freedom in van der Waals and moiré heterostructures.« less

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [2];  [2];  [3]; ORCiD logo [4]; ORCiD logo [1]; ORCiD logo [5]
  1. University of Regensburg (Germany)
  2. Naval Research Laboratory (NRL), Washington, DC (United States)
  3. Technische Universität München, Garching (Germany)
  4. National High Magnetic Field Laboratory, Los Alamos, NM (United States)
  5. Technische Universität München, Garching (Germany); National High Magnetic Field Laboratory, Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA); National Science Foundation (NSF)
OSTI Identifier:
2208794
Report Number(s):
LA-UR-23-20061
Journal ID: ISSN 2053-1583
Grant/Contract Number:  
89233218CNA000001; DMR-1157490
Resource Type:
Accepted Manuscript
Journal Name:
2D Materials
Additional Journal Information:
Journal Volume: 10; Journal Issue: 3; Journal ID: ISSN 2053-1583
Publisher:
IOP Publishing
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; High Magnetic Field Science; TMDs; graphene; valley Zeeman effect; proximity

Citation Formats

Faria Junior, Paulo E., Naimer, Thomas, McCreary, Kathleen M., Jonker, Berend T., Finley, Jonathan J., Crooker, Scott A., Fabian, Jaroslav, and Stier, Andreas V. Proximity-enhanced valley Zeeman splitting at the WS2/graphene interface. United States: N. p., 2023. Web. doi:10.1088/2053-1583/acd5df.
Faria Junior, Paulo E., Naimer, Thomas, McCreary, Kathleen M., Jonker, Berend T., Finley, Jonathan J., Crooker, Scott A., Fabian, Jaroslav, & Stier, Andreas V. Proximity-enhanced valley Zeeman splitting at the WS2/graphene interface. United States. https://doi.org/10.1088/2053-1583/acd5df
Faria Junior, Paulo E., Naimer, Thomas, McCreary, Kathleen M., Jonker, Berend T., Finley, Jonathan J., Crooker, Scott A., Fabian, Jaroslav, and Stier, Andreas V. Fri . "Proximity-enhanced valley Zeeman splitting at the WS2/graphene interface". United States. https://doi.org/10.1088/2053-1583/acd5df. https://www.osti.gov/servlets/purl/2208794.
@article{osti_2208794,
title = {Proximity-enhanced valley Zeeman splitting at the WS2/graphene interface},
author = {Faria Junior, Paulo E. and Naimer, Thomas and McCreary, Kathleen M. and Jonker, Berend T. and Finley, Jonathan J. and Crooker, Scott A. and Fabian, Jaroslav and Stier, Andreas V.},
abstractNote = {The valley Zeeman physics of excitons in monolayer transition metal dichalcogenides provides valuable insight into the spin and orbital degrees of freedom inherent to these materials. Being atomically-thin materials, these degrees of freedom can be influenced by the presence of adjacent layers, due to proximity interactions that arise from wave function overlap across the 2D interface. Here, we report 60 T magnetoreflection spectroscopy of the A- and B- excitons in monolayer WS2, systematically encapsulated in monolayer graphene. While the observed variations of the valley Zeeman effect for the A- exciton are qualitatively in accord with expectations from the bandgap reduction and modification of the exciton binding energy due to the graphene-induced dielectric screening, the valley Zeeman effect for the B- exciton behaves markedly different. We investigate prototypical WS2/graphene stacks employing first-principles calculations and find that the lower conduction band of WS2 at the K / K ′ valleys (the <:tex-math> C B − band) is strongly influenced by the graphene layer on the orbital level. Specifically, our detailed microscopic analysis reveals that the conduction band at the Q point of WS2 mediates the coupling between C B − and graphene due to resonant energy conditions and strong coupling to the Dirac cone. This leads to variations in the valley Zeeman physics of the B- exciton, consistent with the experimental observations. Our results therefore expand the consequences of proximity effects in multilayer semiconductor stacks, showing that wave function hybridization can be a multi-step energetically resonant process, with different bands mediating the interlayer interactions. Such effects can be further exploited to resonantly engineer the spin-valley degrees of freedom in van der Waals and moiré heterostructures.},
doi = {10.1088/2053-1583/acd5df},
journal = {2D Materials},
number = 3,
volume = 10,
place = {United States},
year = {Fri May 26 00:00:00 EDT 2023},
month = {Fri May 26 00:00:00 EDT 2023}
}

Works referenced in this record:

Environmentally sensitive theory of electronic and optical transitions in atomically thin semiconductors
journal, January 2018


Interlayer Excitonic Spectra of Vertically Stacked MoSe2/WSe2 Heterobilayers
journal, May 2021


Synthesis of Large-Area WS2 monolayers with Exceptional Photoluminescence
journal, January 2016

  • McCreary, Kathleen M.; Hanbicki, Aubrey T.; Jernigan, Glenn G.
  • Scientific Reports, Vol. 6, Issue 1
  • DOI: 10.1038/srep19159

Microscopic Understanding of Ultrafast Charge Transfer in van der Waals Heterostructures
journal, December 2021


Quantum Phase Transitions of Trilayer Excitons in Atomically Thin Heterostructures
journal, December 2020


Proximitized materials
journal, January 2019


Moiré excitons in MoSe2-WSe2 heterobilayers and heterotrilayers
journal, March 2021

  • Förg, Michael; Baimuratov, Anvar S.; Kruchinin, Stanislav Yu.
  • Nature Communications, Vol. 12, Issue 1
  • DOI: 10.1038/s41467-021-21822-z

k · p theory for phosphorene: Effective g -factors, Landau levels, and excitons
journal, September 2019


Proximity Effects in Bilayer Graphene on Monolayer WSe 2 : Field-Effect Spin Valley Locking, Spin-Orbit Valve, and Spin Transistor
journal, October 2017


A- and B-exciton photoluminescence intensity ratio as a measure of sample quality for transition metal dichalcogenide monolayers
journal, November 2018

  • McCreary, Kathleen M.; Hanbicki, Aubrey T.; Sivaram, Saujan V.
  • APL Materials, Vol. 6, Issue 11
  • DOI: 10.1063/1.5053699

k · p theory for two-dimensional transition metal dichalcogenide semiconductors
journal, April 2015


Spin-polarized electrons in monolayer MoS2
journal, March 2019

  • Roch, Jonas Gaël; Froehlicher, Guillaume; Leisgang, Nadine
  • Nature Nanotechnology, Vol. 14, Issue 5
  • DOI: 10.1038/s41565-019-0397-y

Boosting proximity spin–orbit coupling in graphene/WSe2 heterostructures via hydrostatic pressure
journal, September 2021

  • Fülöp, Bálint; Márffy, Albin; Zihlmann, Simon
  • npj 2D Materials and Applications, Vol. 5, Issue 1
  • DOI: 10.1038/s41699-021-00262-9

Electron quantum metamaterials in van der Waals heterostructures
journal, November 2018


Twist-angle dependence of the proximity spin-orbit coupling in graphene on transition-metal dichalcogenides
journal, February 2019


Strain-tunable orbital, spin-orbit, and optical properties of monolayer transition-metal dichalcogenides
journal, November 2019


Measurement of Conduction and Valence Bands g -Factors in a Transition Metal Dichalcogenide Monolayer
journal, February 2021


The electronic properties of graphene
journal, January 2009

  • Castro Neto, A. H.; Guinea, F.; Peres, N. M. R.
  • Reviews of Modern Physics, Vol. 81, Issue 1, p. 109-162
  • DOI: 10.1103/RevModPhys.81.109

Interlayer interaction in general incommensurate atomic layers
journal, January 2015


Landau levels in spin-orbit coupling proximitized graphene: Bulk states
journal, October 2020


Revealing the impact of strain in the optical properties of bubbles in monolayer MoSe2
journal, January 2022

  • Covre, F. S.; Faria, P. E.; Gordo, V. O.
  • Nanoscale, Vol. 14, Issue 15
  • DOI: 10.1039/D2NR00315E

Negative infrared photocurrent response in layered WS2/reduced graphene oxide hybrids
journal, December 2014

  • Ratha, Satyajit; Simbeck, Adam J.; Late, Dattatray J.
  • Applied Physics Letters, Vol. 105, Issue 24
  • DOI: 10.1063/1.4903780

Graphene on transition-metal dichalcogenides: A platform for proximity spin-orbit physics and optospintronics
journal, October 2015


Probing the Influence of Dielectric Environment on Excitons in Monolayer WSe 2 : Insight from High Magnetic Fields
journal, October 2016


Counterintuitive gate dependence of weak antilocalization in bilayer graphene/WSe2 heterostructures
journal, March 2022


Chiral Majorana fermions in graphene from proximity-induced superconductivity
journal, June 2020


Trions in MoS2 are quantum superpositions of intra- and intervalley spin states
journal, January 2022


Tuning the proximity effect in a superconductor-graphene-superconductor junction
journal, April 2009


Tight-binding theory of the spin-orbit coupling in graphene
journal, December 2010


Colloquium : Spintronics in graphene and other two-dimensional materials
journal, June 2020


Imaging strain-localized excitons in nanoscale bubbles of monolayer WSe2 at room temperature
journal, July 2020

  • Darlington, Thomas P.; Carmesin, Christian; Florian, Matthias
  • Nature Nanotechnology, Vol. 15, Issue 10
  • DOI: 10.1038/s41565-020-0730-5

Valley Zeeman effect and Landau levels in two-dimensional transition metal dichalcogenides
journal, August 2020


Exciton g factors of van der Waals heterostructures from first-principles calculations
journal, June 2020


Filtering the photoluminescence spectra of atomically thin semiconductors with graphene
journal, March 2020

  • Lorchat, Etienne; López, Luis E. Parra; Robert, Cédric
  • Nature Nanotechnology, Vol. 15, Issue 4
  • DOI: 10.1038/s41565-020-0644-2

Tunable Valley Splitting due to Topological Orbital Magnetic Moment in Bilayer Graphene Quantum Point Contacts
journal, March 2020


Dielectric disorder in two-dimensional materials
journal, August 2019


Effects of strain on electronic properties of graphene
journal, February 2010


Giant proximity exchange and valley splitting in transition metal dichalcogenide/ hBN /(Co, Ni) heterostructures
journal, February 2020


Asymmetric magnetic proximity interactions in MoSe2/CrBr3 van der Waals heterostructures
journal, December 2022


Optospintronics in Graphene via Proximity Coupling
journal, September 2017


Optical imaging of strain in two-dimensional crystals
journal, February 2018


Quantum interference tuning of spin-orbit coupling in twisted van der Waals trilayers
journal, May 2022


Strain-Induced Exciton Hybridization in WS2 Monolayers Unveiled by Zeeman-Splitting Measurements
journal, August 2022


Exposing the trion's fine structure by controlling the carrier concentration in hBN-encapsulated MoS2
journal, January 2021

  • Grzeszczyk, Magdalena; Olkowska-Pucko, Katarzyna; Nogajewski, Karol
  • Nanoscale, Vol. 13, Issue 44
  • DOI: 10.1039/D1NR03855A

g Factor of the Two-Dimensional Interacting Electron Gas
journal, February 1969


Direct evidence for efficient ultrafast charge separation in epitaxial WS 2 /graphene heterostructures
journal, May 2020

  • Aeschlimann, Sven; Rossi, Antonio; Chávez-Cervantes, Mariana
  • Science Advances, Vol. 6, Issue 20
  • DOI: 10.1126/sciadv.aay0761

Spin-orbit coupling and spin relaxation in phosphorene: Intrinsic versus extrinsic effects
journal, October 2016


Opto-Valleytronic Spin Injection in Monolayer MoS 2 /Few-Layer Graphene Hybrid Spin Valves
journal, May 2017


Coupled Spin and Valley Physics in Monolayers of MoS 2 and Other Group-VI Dichalcogenides
journal, May 2012


Enhanced superconductivity in spin–orbit proximitized bilayer graphene
journal, January 2023


First-principles insights into the spin-valley physics of strained transition metal dichalcogenides monolayers
journal, August 2022

  • Faria Junior, Paulo E.; Zollner, Klaus; Woźniak, Tomasz
  • New Journal of Physics, Vol. 24, Issue 8
  • DOI: 10.1088/1367-2630/ac7e21

Band-structure topologies of graphene: Spin-orbit coupling effects from first principles
journal, December 2009


Twist-angle dependent proximity induced spin-orbit coupling in graphene/transition metal dichalcogenide heterostructures
journal, November 2021


Optical control of the valley Zeeman effect through many-exciton interactions
journal, November 2020


Excitonic Linewidth Approaching the Homogeneous Limit in MoS 2 -Based van der Waals Heterostructures
journal, May 2017


Van der Waals heterostructures for spintronics and opto-spintronics
journal, July 2021


First-Principles Study of the Optical Properties of TMDC/Graphene Heterostructures
journal, May 2022


Tunable magneto-optical properties in MoS2 via defect-induced exciton transitions
journal, October 2022


Scanning tunneling spectroscopy of proximity superconductivity in epitaxial multilayer graphene
journal, January 2016


The Effect of Preparation Conditions on Raman and Photoluminescence of Monolayer WS2
journal, October 2016

  • McCreary, Kathleen M.; Hanbicki, Aubrey T.; Singh, Simranjeet
  • Scientific Reports, Vol. 6, Issue 1
  • DOI: 10.1038/srep35154

Reproducibility in density functional theory calculations of solids
journal, March 2016


Optical absorption of interlayer excitons in transition-metal dichalcogenide heterostructures
journal, April 2022


Coulomb engineering of the bandgap and excitons in two-dimensional materials
journal, May 2017

  • Raja, Archana; Chaves, Andrey; Yu, Jaeeun
  • Nature Communications, Vol. 8, Issue 1
  • DOI: 10.1038/ncomms15251

Exciton diamagnetic shifts and valley Zeeman effects in monolayer WS2 and MoS2 to 65 Tesla
journal, February 2016

  • Stier, Andreas V.; McCreary, Kathleen M.; Jonker, Berend T.
  • Nature Communications, Vol. 7, Issue 1
  • DOI: 10.1038/ncomms10643

Excitonic Complexes in n-Doped WS2 Monolayer
journal, March 2021


Giant Spin Lifetime Anisotropy in Graphene Induced by Proximity Effects
journal, November 2017


Trivial and inverted Dirac bands and the emergence of quantum spin Hall states in graphene on transition-metal dichalcogenides
journal, April 2016


Controlling exciton many-body states by the electric-field effect in monolayer MoS 2
journal, April 2021


First-Order Magnetic Phase Transition of Mobile Electrons in Monolayer MoS 2
journal, May 2020


Microscopic theory of the proximity effect in superconductor-graphene nanostructures
journal, May 2008


Strong manipulation of the valley splitting upon twisting and gating in MoSe2/CrI3 and WSe2/CrI3 van der Waals heterostructures
journal, January 2023


Luminescent Emission of Excited Rydberg Excitons from Monolayer WSe 2
journal, March 2019


Spin-orbit coupling in elemental two-dimensional materials
journal, September 2019


Ab Initio Studies of Exciton g Factors: Monolayer Transition Metal Dichalcogenides in Magnetic Fields
journal, June 2020


Prominent room temperature valley polarization in WS2/graphene heterostructures grown by chemical vapor deposition
journal, May 2020

  • Paradisanos, I.; McCreary, K. M.; Adinehloo, D.
  • Applied Physics Letters, Vol. 116, Issue 20
  • DOI: 10.1063/5.0002396

Biaxial strain tuning of the optical properties of single-layer transition metal dichalcogenides
journal, May 2017

  • Frisenda, Riccardo; Drüppel, Matthias; Schmidt, Robert
  • npj 2D Materials and Applications, Vol. 1, Issue 1
  • DOI: 10.1038/s41699-017-0013-7

Exciton g-factors in monolayer and bilayer WSe2 from experiment and theory
journal, September 2020

  • Förste, Jonathan; Tepliakov, Nikita V.; Kruchinin, Stanislav Yu.
  • Nature Communications, Vol. 11, Issue 1
  • DOI: 10.1038/s41467-020-18019-1

Proximity exchange effects in MoSe 2 and WSe 2 heterostructures with CrI 3 : Twist angle, layer, and gate dependence
journal, August 2019


Valley Zeeman Splitting and Valley Polarization of Neutral and Charged Excitons in Monolayer MoTe 2 at High Magnetic Fields
journal, May 2016


Protected Pseudohelical Edge States in Z 2 -Trivial Proximitized Graphene
journal, April 2018


Valley-Dependent Interlayer Excitons in Magnetic WSe2/CrI3
journal, June 2021


Van der Waals heterostructures
journal, July 2013

  • Geim, A. K.; Grigorieva, I. V.
  • Nature, Vol. 499, Issue 7459, p. 419-425
  • DOI: 10.1038/nature12385

Ultrafast pseudospin quantum beats in multilayer WSe2 and MoSe2
journal, August 2022


Theory of Optical Magneto-Absorption Effects in Semiconductors
journal, April 1959

  • Roth, Laura M.; Lax, Benjamin; Zwerdling, Solomon
  • Physical Review, Vol. 114, Issue 1
  • DOI: 10.1103/PhysRev.114.90

Spin–orbit proximity effect in graphene
journal, September 2014

  • Avsar, A.; Tan, J. Y.; Taychatanapat, T.
  • Nature Communications, Vol. 5, Issue 1
  • DOI: 10.1038/ncomms5875

Manipulation of spin transport in graphene/transition metal dichalcogenide heterobilayers upon twisting
journal, November 2021


Analogy and dissimilarity of excitons in monolayer and bilayer of MoSe2
journal, February 2023


Bright excitonic multiplexing mediated by dark exciton transition in two-dimensional TMDCs at room temperature
journal, January 2022

  • Katznelson, Shaul; Cohn, Bar; Sufrin, Shmuel
  • Materials Horizons, Vol. 9, Issue 3
  • DOI: 10.1039/D1MH01186C

Berry phase, hyperorbits, and the Hofstadter spectrum: Semiclassical dynamics in magnetic Bloch bands
journal, March 1996


Magnetoreflection spectroscopy of monolayer transition-metal dichalcogenide semiconductors in pulsed magnetic fields
journal, July 2016

  • Stier, Andreas V.; McCreary, Kathleen M.; Jonker, Berend T.
  • Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena, Vol. 34, Issue 4
  • DOI: 10.1116/1.4948992

Direct exciton emission from atomically thin transition metal dichalcogenide heterostructures near the lifetime limit
journal, September 2017


Electrical Tuning of Exciton Binding Energies in Monolayer WS 2
journal, September 2015


Revealing exciton masses and dielectric properties of monolayer semiconductors with high magnetic fields
journal, September 2019


Large-Area Synthesis of Continuous and Uniform MoS 2 Monolayer Films on Graphene
journal, August 2014

  • McCreary, Kathleen M.; Hanbicki, Aubrey T.; Robinson, Jeremy T.
  • Advanced Functional Materials, Vol. 24, Issue 41
  • DOI: 10.1002/adfm.201401511

Rigid Band Shifts in Two-Dimensional Semiconductors through External Dielectric Screening
journal, November 2019


Induced spin-orbit coupling in twisted graphene–transition metal dichalcogenide heterobilayers: Twistronics meets spintronics
journal, August 2019


Valley-filling instability and critical magnetic field for interaction-enhanced Zeeman response in doped WSe2 monolayers
journal, December 2021


Subcycle contact-free nanoscopy of ultrafast interlayer transport in atomically thin heterostructures
journal, May 2021


Enhanced valley splitting of WSe2 in twisted van der Waals WSe2/CrI3 heterostructures
journal, February 2022


WIEN2k: An APW+lo program for calculating the properties of solids
journal, February 2020

  • Blaha, Peter; Schwarz, Karlheinz; Tran, Fabien
  • The Journal of Chemical Physics, Vol. 152, Issue 7
  • DOI: 10.1063/1.5143061