Equipment Descriptions | QNS Collaborative Fellowship

Key Equipment

QNS is operating three ESR-STM systems that are equipped: a) with high-frequency equipment, b) operate at low temperature, and c) in vector magnetic fields.

• One commercial tool, nicknamed Alice, operates at 0.4 K for almost two days, after which the cooling fluids need to be replenished, which causes a downtime of about 5 hours.

• A second system, which is home built and nicknamed Bob, uses a dilution refrigerator and is able to continuously operate at temperatures as low as 30 mK.

• Our third ESR-STM system, nicknamed Eve, is fully home built which gives us the most flexibility to incorporate novel upgrades. It operates in continuous circulation at 1.2 K.

ALICE ESR-STM System

Commercial system

Received: December 2018

First Results: February 2019

Key results

• First ever ESR-STM on a molecule

• Pulsed ESR-STM

• ESR double resonance on two spins

Specifications

Temp: 0.4 K in single shot mode

1.8 K in continuous mode

Magnet: 6 T perpendicular to sample

5 T in plane

2 T vector field in any angle

ESR: Best range: 10-20 GHz

Representative paper:

Universal quantum control of an atomic spin qubit on a surface

Wang, Y., Haze, M., Bui, H.T., Soe, We-hyo., Aubin, H., Ardavan, A., Heinrich, A.J., Phark, S., npj Quantum Inf 9, 48 (2023)

BOB ESR-STM System

Partially home-built system

Start of assembly: August 2019

First Results: March 2020

Key results

• ESR as a function of magnetic field angle

• Spins on superconductor spectroscopy

• ESR double resonance on two spins

Specifications

Temp: 0.01 K in continuous mode

Higher temperatures are possible

Magnet: 6 T perpendicular to sample

9 T in plane

3 T vector field at any angle

ESR: Best range: DC-35 GHz (Tip & Antenna)

Representative paper:

Anisotropic Hyperfine Interaction of Surface-Adsorbed Single Atoms

Kim, J., Noh, K., Chen, Yi., Donati, F., Heinrich, A., Wolf, C., Bae, Y., Nano Letters 2022 22 (23), 9766-9772

EVE ESR-STM System

Fully home-built system

Start of assembly: September 2019

First Results: August 2021

Key results

ESR at variable temperatures (up to 10 K)
ESR sensor attached to the STM tip

Specifications

Temp: 1.3 K in continuous mode with He-4

1.1 K in single-shot mode with He-4

Lower temperature with He-3 planned

Magnet: 4 T perpendicular to sample

6 T in plane

4 T vector field at any angle

ESR: Up to 40 GHz with antenna

ESR on tip OR on antenna

Representative paper:

Development of a scanning tunneling microscope for variable temperature electron spin resonance

Hwang, J., Krylov, D., Elbertse, R.,Yoon, S., Ahn, T., Oh, J., Fang, L., Jang, W., Cho, F., Heinrich, A., Bae, Y., Rev Sci Instrum 1 September 2022; 93 (9): 093703

CHARLIE ESR-STM System

Fully home-built system

Start of assembly: May 2021

First Results: October 2022

Key results

• World best vibration noise level: 20 fA/sqrt(Hz) @ 10 mV, 1 nA (Tunneling condition)
• Measurement of Landau-Zener transition gap in picoelectron-volts

Specifications

Temp: 1.1 K in continuous mode with He-4
0.99 K in single-shot mode with He-4
Lower temperature with He-3 planned

Magnet: 0.25 T (0.1 T/s) perpendicular to sample

1 T (0.5 T/s) in-plane

ESR: Up to 30 GHz 3 RF cables