Seminar Announcement

Speaker: Ying Jiang, Int. Center for Quantum Materials, School of Physics, Peking

Location: HIT E 41.1

Date: Friday, 10 July 2015

Time: 11.00 h

Title:

Probing quantum nature of hydrogen bond with scanning probe microscopy and spectroscopy

Abstract:

It has been known that the complexity of hydrogen-bonding interaction largely arises from the quantum nature of light hydrogen nuclei (proton). The so-called nuclear quantum effects (NQEs) in terms of tunneling and zero-point motion play important roles in the structure, dynamics, and macroscopic properties of hydrogen-boned materials. Despite enormous theoretical efforts on pursuing proper treatment of the nuclear motion at a quantum-mechanical level, accurate and quantitative description of NQEs on the hydrogen-bonding interaction has proven experimentally challenging. In this talk, I will present our recent progresses on probing NQEs of interfacial water at single bond limit using a low-temperature scanning probe microscope (SPM). By gating the molecular frontier orbitals near the Fermi level via tip-water coupling, we are able to access the internal degrees of freedom of water molecules and locate the protons in real space [1,2]. These techniques allow us not only to directly visualize the many-body proton tunneling within the H-bonded network [3], but also to quantify the impact of nuclear quantum fluctuation on the strength of hydrogen bonds [4]. Our work opens up the possibility of directly assessing, in experiment, the impact of NQEs on hydrogen-bonding interaction, which is essential for elucidating the quantum nature of the hydrogen bonds.

[1] J. Guo et al., Nature Materials 13, 184 (2014).

[2] J. Chen et al., Nature Communications 5, 4056 (2014).

[3] X. Meng et al., Nature Physics 11, 235 (2015).

[4] J. Guo et al., submitted.

Biography

Dr. Ying Jiang received his Bachelor degree from Beijing Normal University in 2003 and his Ph.D from Institute of Physics, Chinese Academy of Sciences (CAS) in 2008. He has been a visiting scientist in Forschungszentrum Jülich GmbH in Germany (2006-2007). After working as a Postdoctoral Associate in University of California, Irvine (2008-2010), he joined International Center for Quantum Materials of Peking University as an assistant professor and was promoted to associate professor in 2013. He has published more than 20 peer-reviewed papers in Science, Nature Series, Phys. Rev. Series, and so on. He is currently interested in the electronic, magnetic, vibrational, and optical properties of single molecules/nanostructures and low-dimensional quantum materials, as well as the related ultrafast dynamics processes. He is also interested in development of new techniques and instrumentation associated with scanning probe microscopes.

sig. Lei Wang