Quantum Materials, Devices, and Systems at 20 Years of NNIRobert M Westervelt Harvard University

http://CIQM.Harvard.edu

STC for Integrated Quantum Materials (2013-2023) DMR-1231319NNCI Site - CNS at Harvard (2015-2025) EECS-2025158Nanoscale Science & Engineering Center (2001-2012) PHY-06-46094

Nanotechnology Frontiers at 20 years of NNIProceedings, December 1, 2020, www.nseresearch.org/2020/

1 nm

0.1 nm

0.1 eV

10 eV

energy0.001 eV

size 10 nm

10 µm

0.1 µm

1 µm

light

Quantum Science & Technology

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22 nm CMOS

quantum electronics & photonics with atomic-scale devices

electrons

T = 300 K

atomic NV center

vdW hetero-

structures

atomic layer graphene

color center diamond

diamond photonics

2

New Particles in Quantum Materialselectrons & photons | Bloch waves in solids | new quantum particles

vacuum

electron photon

–

solidsphononslower photon

–e & h with m*

quantum materials

e & h, massless no energy gap

graphene

topological edge states for B = 0

topological insulators

300 Kqubit

diamond NV centers

atom

3

STC for Integrated Quantum MaterialsHarvard, Howard, MIT, Museum of Science, Boston

Vision:Create atomic-scale devices and systems from quantum

materials for quantum sensors, quantum networks, and quantum computers.

Quantum MaterialsAtomic Layers: Graphene, BN, MoS2 – atomic scale devices Topological Insulators – topologically protected data channels NV Center Diamond – 1 atom memory sites, quantum sensors

Materials & Device Innovation Cycle

Growth & Processing

Atomic Modeling & Understanding

Device Fabrication &

Characterization

JEOL HR STEM

CNSImaging

MBE

UHV tr

MBE & CVDMaterialsGrowth

Experimental Test DataTheory

5

CIQM Research Areas

Quantum Networks with Solid State Quantum Emitters – Marko Loncar

Topologically Protected Qubits Amir Yacoby & Pablo Jarillo-Herrero

Novel vdW Heterostructures Philip Kim

twisted graphene bilayer

Moire pattern

New Topological Crystals Joseph Checkelsky

Superconductor & Mott Insulator - Magic Angle Twisted Bilayer

Y. Cao et al. Nature 556, 43 (2018); Nature 556, 80 (2018).

–0.2 0.2 0 –0.2

–40

0.2

–20

0

20

40

kx (nm–1)yk (nm–1)

Ener

gy,

E(m

eV)

Freestanding graphene (×1,000)

0 = 1.05°

EF

–1 –2DOS (eV nm )100

–100

–5

0

5

10

0.1

0.2

0.3

0.4

0.5

0.6

–1.4 –1.2

1

2

3

Carrier density, n (1012 cm–2)Carrier density, n (1012 cm–2)

Tem

pera

ture

, T(K

)

Tem

pera

ture

, T(K

)8 4 0b

Rxx (kQ) Rxx (kQ)

Mott

Superconductor

–1.8 –1.6

Superconductor

Superconductor

–1.8 –1.6 –1.4 –1.2 –1.0 –0.8

Metal Metal

010 5c

Mott MetalMetal

M1, = 1.16° M2, = 1.05°

Twisted single layer graphene (tBG)

Magic angle condition

Mott Insulator &

Superconductor

Bistritzer & MacDonald, PNAS 108, 12233 (2011).

magic-angle twisted bilayer

graphene

a

Pablo Jarillo-Herrero

Tim Kaxiras

Topology: A Mathematical Concept with use in Electronics

(1964)

Mobius Shawl Topological in Construction8

(1964)

Topology: A Mathematical Concept with use in Electronics

2Mobius Shawl Topological in Construction

Fe3Sn2 New Kagome Metal

STEM Image theory

Ye, Bell, Fu, Comin, Checkelsky et al., Nature (2018).

Fe

Sn

Kagome Bilayer

Flat Energy Band promotes correlations

Joe Checkelsky

Guo & Franz,PRB 80 113102 (2009).

Quantum Emitters for Quantum Networks

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color center qubits in diamondMarko Loncar

quantum emitter in strained 2D sheets

qubit spin to photon

On-chip Diamond

Nanophotonics Lukin & Loncar

SEM images: (a) resonator array with (b) diamond nanobeam photonic cavities with SiV color centers (c) waveguide support (d, e) diamond tapers for > 98% fiber-coupling. (f) SiV fluorescence is collected by optical fiber. (g) Image of optical fiber taper in contact with diamond waveguide taper.[Burek et al. NatureComm. (2014)]

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Science & Education Community

Industrial & Venture Capital

Partners

Harvard innovation lab

NewQuantum Partners

$120 round trip

College Network

PublicOutreach

IndustrialOutreach

$150 round trip

Industry

13

Crystal Virtual Reality @ Museum of Science Nanodays

American Sign Language signs for STEMplease see the website aslclear.com

Barbara Spiecker

The Learning Center for the Deaf www.tlcdeaf.org

Mandy Houghton

Quantum Computing R&D Partners

Thomas Ohki, KC Fong & team CIQM faculty members

William Oliver & team Lincoln Laboratory & MIT CIQM faculty members

NNCI Site at Harvard University (http://www.nnci.net)

NSF ECCS-2025158

Thank you!