General Lab Information

Dr. Percy Zahl

Senior Staff Scientist, Interface Sciences/Catalysis, Center for Functional Nanomaterials

Dr. Percy Zahl

Brookhaven National Laboratory

Center for Functional Nanomaterials
Bldg. 735, Room 2042
P.O. Box 5000
Upton, NY 11973-5000

(631) 344-2968

Currently leading the Low Temperature (LT) STM and NC-AFM/HR-AFM facility at CFN and providing world-class expertise for HR-AFM imaging together with all related experimental services and operating the microscope. A unique service: The world wide only proposal based HR-AFM service at a user facility open to any one.

Always open to new ideas and establishing new collaborations.

For over 20 years (since year 2000) project manager and lead programmer of GXSM. A open source SPM (and more) control software. Providing a DSP + FPGA hardware based data acquisitions and instrument control platform. A world wide in use SPM control solution with easy acessible and comercial available hardware running non proprietary and user accessible software. Further providing online support and help with any custom project as possible.

Expertise | Research | Education | Appointments | Publications | Highlights | Awards


  • Wide range of fundamental physics.
  • Surface science and epitaxy, and working at "single" molecule and atom scale.
  • Basic knowledge of many Surface Science tools: LEED, SPA-LEED, XRD, XSW, AUGER, SEM, FIB and ultra clean surface preparations in UHV.
  • Expert for various kinds of Scanning Probe Microscopy: STM, AFM, NC-AFM and HR-AFM in particular at low temperature (5K) plus related Instrumentation R&D.
  • Fundamental chemistry with particular recent interest in molecular structure and sub molecular binding phenomena in complex hydrocarbons. Expertise in various methods to deposit few individual molecules from various sources (only miniature amounts required) — including dissolved in select (non toxic) solvents — onto ultra clean metal substrates.
  • Beyond Physics: Knowledgeable in electronics, analog and digital, hard- and software design, FPGA/Verilog, C/C++, Python, familiar with basic "AI" tools, web design, mysql and more. Experienced in CAD design and precision machining, milling, etc.

Research Activities

Most recent research includes:

  • On surface synthesis of novel functionalized GNR nano ribbons using custom designed pre cursor molecules. Structure and electronic property evaluation using ultra resolution NC-AFM and STM together with STM based spectroscopy. (Collaboration with Univ. Nebraska)
  • Pushing and exploring the limits of NC-AFM imaging of various aromatic molecules with focus on intra molecule binding details. (Collaboration with Exxon Mobil)
  • Developing hard- and software algorithms for optimized Scanning Quantum Dot Microscopy (SQDM). (International Collaborations, Forschungszentrum Jülich, Germany and Haward)
  • Work on deploying AI methods for autonomous SPM operations.
  • Developing novel NC-AFM frequency detection algorithms and FPGA based hardware implementations in the context of exploring novel advanced measurement techniques.


1995-1996: Leibniz University Hannover, Germany, Diplom Thesis, Physics

1996-2000: Leibniz University Hannover, Germany Ph.D., Physics

Professional Appointments

Research and Professional Experience

  • 2020-present: Senior Staff Scientist at Brookhaven National Laboratory, Center for Functional Nanomaterials
  • 2005-2020: Staff Scientist (Scientific Associate) at Brookhaven National Laboratory, Center for Functional Nanomaterials
  • 2003-2005: IBM Zürich, Zürich Research Laboratory, Post-Doc
  • 2001-2003: Colorado School of Mines, Colorado, Post-Doc

Synergistic Activities

  • 1995-present:  Member of Deutsche Physikalische Gesellschaft
  • 2000-present: Project leader and lead programmer of GXSM — a open source software for generic Scanning Probe data acquisation and instrument control — like STM, AFM and more. (License: GPL, managed at SourecForge since 2000 and most recent code base migrated to GitHub: and /Gxsm4.
  • 2022: Organized 1st SPM Workshop at CFN+NSLS Users Meeting
  • 2023: Organized 2nd SPM Workshop at CFN+NSLS Users Meeting
  • 2023: Organizer of CFN Summer Sundays 2023

Selected Publications

  • Wang X, Zahl P, Wang H, et al (2024) How Precisely Can Individual Molecules Be Analyzed? A Case Study on Locally Quantifying Forces and Energies Using Scanning Probe Microscopy. ACS Nano.
  • Jacobse PH, Sarker M, Saxena A, et al (2024) Tunable Magnetic Coupling in Graphene Nanoribbon Quantum Dots. Small.
  • Fang S, Zahl P, Wang X, et al (2023) Direct Observation of Twin van der Waals Molecular Chains. The Journal of Physical Chemistry Letters 14:10710–10716.
  • Chakraborty A, Zahl P, Dai Q, et al (2023) Frontier Orbital Degeneracy: A New Concept for Tailoring the Magnetic State in Organic Semiconductor Adsorbates. The Journal of Physical Chemistry C.
  • Arias S, Zhang Y, Zahl P, Hollen S (2023) Autonomous Molecular Structure Imaging with High-Resolution Atomic Force Microscopy for Molecular Mixture Discovery. The Journal of Physical Chemistry A.
  • Chakraborty A, Zahl P, Dai Q, et al (2022) HATCN on Ag(111): a Molecular Kondo Switch with Intrinsic Magnetic Bistability
  • Lawson B, Zahl P, Hybertsen MS, Kamenetska M (2022) Formation and Evolution of Metallocene Single-Molecule Circuits with Direct Gold-π Links. Journal of the American Chemical Society 144:6504–6515.
  • Wu R, Eltinge S, Drozdov IK, et al (2022) Micrometre-scale single-crystalline borophene on a square-lattice Cu(100) surface. Nature Chemistry 14:377–383.
  • Lawson B, Zahl P, Hybertsen MS, Kamenetska M (2022) Formation and Evolution of Metallocene Single-Molecule Circuits with Direct Gold-π Links. Journal of the American Chemical Society 144:6504–6515.
  • Zahl P, Yakutovich AV, Ventura-Macías E, et al (2021) Hydrogen bonded trimesic acid networks on Cu(111) reveal how basic chemical properties are imprinted in HR-AFM images. Nanoscale 13:18473–18482.
  • Larson AM, Balema TA, Zahl P, et al (2020) Hypothetical Efficiency of Electrical to Mechanical Energy Transfer during Individual Stochastic Molecular Switching Events. ACS Nano 14:16558–16564.
  • Eads CN, Zhong J-Q, Kim D, et al (2020) Multi-modal surface analysis of porous films under operando conditions. AIP Advances 10:.
  • Garlant A, Maughan B, Zahl P, Monti OLA (2020) H2Pc and pentacene on Cu(110)-(2×1)O: A combined STM and nc-AFM study. Surface Science 696:121590.
  • Doud EA, Starr RL, Kladnik G, et al (2020) Cyclopropenylidenes as Strong Carbene Anchoring Groups on Au Surfaces. Journal of the American Chemical Society 142:19902–19906.
  • Teeter JD, Zahl P, Mehdi Pour M, Costa PS, Enders A, Sinitskii A (2019) On-Surface Synthesis and Spectroscopic Characterization of Laterally Extended Chevron Graphene Nanoribbons. ChemPhysChem 20:2281–2285. doi: 10.1002/cphc.201900445
  • Zahl P, Zhang Y (2019) Guide for Atomic Force Microscopy Image Analysis To Discriminate Heteroatoms in Aromatic Molecules. Energy & Fuels 33:4775–4780. doi: 10.1021/acs.energyfuels.9b00165
  • Wu R, Drozdov IK, Eltinge S, Zahl P, Ismail-Beigi S, Bo┼żovic I, Gozar A (2018) Large-area single-crystal sheets of borophene on Cu(111) surfaces. Nature Nanotechnology 14:44–49. doi: 10.1038/s41565-018-0317-6
  • Larson AM, van Baren J, Kintigh J, Wang J, Tang J-M, Zahl P, Miller GP, Pohl K (2018) Lateral Standing of the Pentacene Derivative 5,6,7-Trithiapentacene-13-one on Gold: A Combined STM, DFT, and NC-AFM Study. The Journal of Physical Chemistry C 122:11938–11944. doi: 10.1021/acs.jpcc.8b03633
  • Li M, Chen J, Routh PK, Zahl P, Nam C, Cotlet M (2018) Distinct Optoelectronic Signatures for Charge Transfer and Energy Transfer in Quantum Dot–MoS 2 Hybrid Photodetectors Revealed by Photocurrent Imaging Microscopy. Advanced Functional Materials 28:1707558. doi: 10.1002/adfm.201707558
  • Shekhirev M, Zahl P, Sinitskii A (2018) Phenyl Functionalization of Atomically Precise Graphene Nanoribbons for Engineering Inter-ribbon Interactions and Graphene Nanopores. ACS Nano 12:8662–8669. doi: 10.1021/acsnano.8b04489
  • Jnawali G, Klein C, Wagner T, Hattab H, Zahl P, Acharya DP, Sutter P, Lorke A, Horn-von Hoegen M (2012) Manipulation of Electronic Transport in the Bi(111) Surface State. Physical Review Letters. doi: 10.1103/physrevlett.108.266804
  • Zahl P, Wagner T, Möller R, Klust A (2010) Open source scanning probe microscopy control software package GXSM. Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena 28:C4E39–C4E47. doi: 10.1116/1.3374719
  • Sutter P, Zahl P, Sutter E, Bernard JE (2003) Energy-Filtered Scanning Tunneling Microscopy using a Semiconductor Tip. Physical Review Letters. doi: 10.1103/physrevlett.90.166101

Research Highlights

'No Linker' Single-Molecule Circuits

Imaging the Chemical Fingerprints of Molecules

Atomically-Precise Assembly of Graphene Nanoribbons

Looking at Atoms to Make Cleaner Fuels from Petroleum

Solving the Riddle of the Crystal Structure of Borophene

BNL Newsroom:

Next-Generation Software Supports Explorations Beyond the Nanoworld into the Intramolecular Picoworld

Percy Zahl: Mapping Materials at the Nanoscale

Center for Functional Nanomaterials Selects Winners of Image Contest

Awards & Recognition

2012 George T. Hanyo Award (AVS) for ``outstanding leadership in the development of state-of-the-art, open-source software — called GXSM or the Gnome X Scanning Microscopy project — for data acquisition and analysis in scanning probe microscopy and spectroscopy.''

Patent: "Defining a pattern on a substrate - US Patent 7315367. (Filed at IBM Zurich)"

Dr. Percy Zahl

Brookhaven National Laboratory

Center for Functional Nanomaterials
Bldg. 735, Room 2042
P.O. Box 5000
Upton, NY 11973-5000

(631) 344-2968

Dr. Percy's Links