This article is from the archives of the UB Reporter.

Tackling the mysteries of nanostructures

Physicist Ganapathy studies electron transport in nanostructures

Published: May 3, 2007

Reporter Staff Writer

There's a good explanation for the eight-foot pit in the center of the lab in Fronczak Hall, UB physicist Sambandamurthy Ganapathy tells a visitor from the Reporter.


A dilution refrigerator is being installed in Sambandamurthy Ganapathy’s lab in Fronczak Hall that will generate temperatures near absolute zero and extremely powerful magnetic fields in order to create quantum mechanical phenomena for research purposes.

Slated for installation beneath the floor this summer is a huge, high-tech piece of equipment known as a dilution refrigerator, which, he says, will generate temperatures near absolute zero and magnetic fields 300,000 times more powerful than the Earth's magnetosphere in order to create quantum mechanical phenomena for scientific observation.

"We're setting up a new lab to study quantum effects in nanostructures," says Ganapathy, who joined the Department of Physics, College of Arts and Sciences, as an assistant professor this past fall. "Our main experiments will be studying electron transport in nanostructures at very low temperatures and at high magnetic understand how electrons go from one place to another in one-dimensional and zero-dimensional materials."

There is no lack of knowledge about the behavior of electrons in three-dimensional objects, such as the familiar copper wires through which electrons travel with little resistance; but Ganapathy says scientists possess scant information about the behavior of electrons in lower-dimensional objects. These include one-dimensional objects, such as carbon nanotubes, and zero-dimensional objects, such as quantum dots.

"In quantum mechanical behavior, electrons don't travel smoothly," Ganapathy notes. "They jump from one place to another because the energy levels are quantized."

Extremely low temperatures and powerful magnetic fields encourage this "quantum transport" to take place in nanomaterials, he says.

Electron transport in nanomaterials is important because nanostructures often are looked upon as the future of silicon-based consumer electronics, which, he explains, are expected to saturate in the next 10 to 20 years. "At this stage, it's not clear what will be the replacement for silicon in the long run," says Ganapathy. "Several groups in the world are at work on new electronic nanomaterials that could replace silicon technology in consumer electronics."

Although these potential devices are far from the marketplace, Ganapathy says scientists whose work provides a basic grasp of the unique properties of nanomaterials are at the forefront of a process that will enable engineers to create the next generation of consumer electronic devices.

"Our efforts are to find out how good these materials are for electronic devices," he says. "Research in this field is cutting-edge and has large potential for industrial collaborations."

Ganapathy's interest in physics traces back to his time as an undergraduate at St. John's College in Tirunelveli, India. He went on to receive a master's degree from the American College in Madurai, India, in 1994, and a doctorate from the Indian Institute of Science in Bangalore in 2000,

"Physics deals with the laws of nature," he says. "I wanted to know more about how things work in the world...force and momentum and acceleration are concepts that have direct relevance to what you do every day." He adds that he pursued postgraduate education out of a desire to understand electronic behavior at the atomic level.

In 2001, Ganapathy received a three-year postdoctoral fellowship to the Weizmann Institute of Science in Israel—one of the top scientific research facilities in the world—and then in 2004, traveled to the United States to work with Nobel Prize winner Daniel C. Tsui and with Lloyd Engel in a joint-appointed fellowship to Princeton University and the National High-Magnetic Field Laboratory (NHMFL) in Tallahassee, Fla.

"At Weizmann, I worked on superconducting materials, and at Princeton and NHMFL I worked on semiconductor nanostructures," he says, pointing out that these experiences brought about valuable insights into the physics of nanostructures, as well as nanofabrication and dilution refrigeration techniques. Ganapathy's work has resulted in the publication of more than 20 articles in leading physics journals. Last year, a paper co-written by Ganapathy, Tsui and colleagues at Princeton and NHMFL, which was published in the journal Nature Physics, provided an important contribution to modern research into the melting behavior of crystalline electron solids and electron-electron interaction. Two others papers are in the manuscript stage.

The strong growth of the UB physics department in response to the identification of integrated nanostructured systems as a strategic strength under the UB 2020 strategic planning process was an important factor in his decision to come to UB last fall, says Ganapathy.

"There are several departments that participate in this integrated nanostructures project, such as Chemistry, Electrical Engineering and Physics, to name a few," he notes, "so this gives me an opportunity to collaborate with colleagues in other departments and develop truly interdisciplinary research projects."

Ganapathy says his activities this academic year have focused on preparing his lab, including working with graduate students on equipment design and computer programs to control instruments that must detect the smallest possible electrical signals. He says the lab will receive three large, custom-built pieces of equipment in the coming months. The nanodevices used in his experiments will come from UB's nanofabrication facilities in Bonner Hall.

"I teach classes, too," says Ganapathy. "I taught an introductory freshman physics course last semester—it was a lot of fun because this is the first time I'm teaching a freshman-level course—and this semester I'm teaching a modern physics course for junior physics majors."

A resident of Amherst, Ganapathy moved to the Buffalo area with his wife, Kalyani, and 2-year-old daughter, Amrita. A native of a tropical region in India, Ganapathy says his biggest adjustment to Western New York has been the weather.

Low temperatures aren't enough to keep him and his family from exploring the region, however.

"It's pretty exciting; there are a lot of things you can access nearby," he says, pointing to destinations such as the Adirondack and Smoky mountains. "Several people in India want to visit us because we're so close to Niagara Falls."