Rutgers physicists have discovered that electrons in certain metal compounds can "gain weight" near absolute zero, offering new insights into the behavior of electrons in materials.
The findings, published in the journal Nature Physics, could have implications for the development of new electronic devices and materials.
"Electrons are usually thought of as being massless particles, but in certain materials, they can behave as if they have mass," said study lead author Johannes Gooth, a postdoctoral researcher in the Department of Physics and Astronomy at Rutgers University-New Brunswick. "We found that in a specific class of materials called metal-organic frameworks (MOFs), electrons can gain weight near absolute zero due to interactions with the surrounding molecules."
MOFs are a class of porous materials made up of metal ions connected by organic molecules. They have a wide range of potential applications, including gas storage, catalysis, and drug delivery.
In the study, the researchers used a technique called scanning tunneling microscopy to measure the effective mass of electrons in a MOF called Cu3(BTC)2. They found that the effective mass of electrons in the MOF increased by a factor of about 10 near absolute zero.
"This is a very significant change in the effective mass of electrons," said study co-author Fernando Camino, a professor of physics and astronomy at Rutgers. "It's the first time that such a large change in the effective mass of electrons has been observed in a MOF."
The researchers believe that the increase in the effective mass of electrons in Cu3(BTC)2 is due to interactions between the electrons and the molecules of the MOF. At low temperatures, the molecules of the MOF vibrate less, which allows the electrons to interact with them more strongly. This interaction leads to an increase in the effective mass of the electrons.
"Our findings provide new insights into the behavior of electrons in materials," Gooth said. "This could have implications for the development of new electronic devices and materials."
