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Detection of a Chirality-Induced Spin Selective Quantum Capacitance in α-Helical Peptides
Pius Markus Theiler1, Christian Ritz1, Raphael Hofmann2
1Nanotechnology Group, ETH Zürich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland.
Nano Letters
|August 31, 2023
Summary
Advanced Kelvin probe force microscopy reveals quantum capacitance and surface potential shifts in peptide monolayers, challenging the need for global charge transport in chirality-induced spin selectivity effects.
Area of Science:
- Surface science
- Quantum phenomena
- Molecular electronics
Background:
- Chirality-induced spin selectivity (CISS) effect describes spin polarization in chiral molecules.
- Understanding the fundamental mechanisms of CISS is crucial for spintronics and molecular electronics.
Purpose of the Study:
- To investigate the role of quantum capacitance and surface potential in CISS.
- To determine if global charge transport is necessary for CISS effects.
- To experimentally validate theoretical models of CISS.
Main Methods:
- Utilized advanced Kelvin probe force microscopy (KPFM) to simultaneously measure quantum capacitance and surface potential.
- Studied an alpha-helical peptide monolayer.
- Developed a theoretical model based on a triangular quantum well with electron-electron interactions.
Main Results:
- Observed shifts in quantum capacitance and surface potential upon toggling magnetic polarization and enantiomer.
- The developed model successfully calculated the electrical potential profile from experimental data.
- Demonstrated that CISS effects can occur without global charge transport.
Conclusions:
- Experimental findings support the theoretical model proposed by Fransson et al.
- Quantum capacitance measurements offer a novel method for testing and refining CISS theories.
- CISS effects are not solely dependent on global charge transport.
Keywords:
Kelvin probe force microscopychirality-induced spin selectivityquantum capacitancespinterfaceMore Related Videos
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