Chain-like structure elements in Ni40Ta60 metallic glasses observed by scanning tunneling microscopy.
The structure of metallic glasses is a long-standing question because the lack of long-range order makes diffraction based techniques difficult to be applied. Here, we used scanning tunneling microscopy with large tunneling resistance of 6 GΩ at low temperature in order to minimize forces between probe and sample and reduce thermal fluctuations of metastable structures. Under these extremely gentle conditions, atomic structures of Ni40Ta60 metallic glasses are revealed with unprecedented lateral resolution. In agreement with previous models and experiments, icosahedral-like clusters are observed. The clusters show a high degree of mobility, which explains the need of low temperatures for stable imaging. In addition to icosahedrons, chain-like structures are resolved and comparative density functional theory (DFT) calculations confirm that these structures are meta-stable. The co-existence of icosahedral and chain-like structures might be an key ingredient for the understanding of the mechanical properties of metallic glasses.
Department of Physics, University of Basel, Klingelbergstr. 82, 4056 Basel, Switzerland.
Rémy
R
Pawlak
Department of Physics, University of Basel, Klingelbergstr. 82, 4056 Basel, Switzerland.
Laurent
L
Marot
1] Department of Physics, University of Basel, Klingelbergstr. 82, 4056 Basel, Switzerland [2] Department of Physics, Shahid Beheshti University, Evin, 19839 Theran, Iran.
Ali
A
Sadeghi
Department of Physics, University of Basel, Klingelbergstr. 82, 4056 Basel, Switzerland.
Shigeki
S
Kawai
Department of Physics, University of Basel, Klingelbergstr. 82, 4056 Basel, Switzerland.
Thilo
T
Glatzel
Department of Physics, University of Basel, Klingelbergstr. 82, 4056 Basel, Switzerland.
Peter
P
Reimann
Department of Physics, University of Basel, Klingelbergstr. 82, 4056 Basel, Switzerland.
Stefan
S
Goedecker
Department of Physics, University of Basel, Klingelbergstr. 82, 4056 Basel, Switzerland.
Hans-Joachim
HJ
Güntherodt
Department of Physics, University of Basel, Klingelbergstr. 82, 4056 Basel, Switzerland.
Ernst
E
Meyer