Purdue University researchers have made a groundbreaking discovery in the field of quantum technology with their development of patent-pending one-dimensional boron nitride nanotubes (BNNTs) containing spin qubits. These BNNTs have shown to be more sensitive in detecting off-axis magnetic fields at high resolution compared to traditional diamond tips used in scanning probe magnetic-field microscopes.
Tongcang Li, a renowned professor of physics and electrical and computer engineering at Purdue University, leads a team that has successfully created BNNTs with optically active spin qubits. Alongside him are graduate students Xingyu Gao, Sumukh Vaidya, and Saakshi Dikshit, who are co-authors of a paper recently published in the esteemed journal Nature Communications.
“BNNT spin qubits have proven to be more responsive in detecting off-axis magnetic fields compared to diamond nitrogen-vacancy centers, which are primarily sensitive to parallel fields and not perpendicular ones,” Li explained. “Moreover, BNNTs are a more cost-effective and robust alternative to fragile diamond tips.”
The applications of BNNTs are diverse, ranging from quantum-sensing technology for measuring magnetic field changes to advancements in the semiconductor industry and nanoscale magnetic resonance imaging (MRI).
“The potential for BNNT spin qubits is immense, with implications in various fields such as quantum science, memory storage, and medical and semiconductor industries,” Gao pointed out.
Li has taken the initiative to disclose the nanotube spin qubits to the Purdue Innovates Office of Technology Commercialization, which is in the process of seeking patents to safeguard the intellectual property.
Testing and developing BNNT spin qubits
The BNNT spin qubit system underwent rigorous testing within a custom-built laboratory setup equipped with lasers, detectors, and signal generators to manipulate the quantum state of the nanotube spin qubits.
“These BNNT spin qubits display high sensitivity to magnetic fields and exhibit optically detected magnetic resonance,” Vaidya elaborated. “Under the influence of a magnetic field, the energy levels of the spin qubits within the BNNTs undergo changes that can be quantified using light.”
In initial demonstrations, BNNTs performed comparably to diamond tips, but the team anticipates achieving superior results due to the smaller spatial dimensions of the boron nitride nanotubes.
“By enhancing the spatial resolution and magnetic field sensitivity of the BNNT spin qubit system, we aim to enable quantum sensing at the atomic scale,” Dikshit explained.
“This enhancement would facilitate highly precise scanning of surface magnetic properties, with applications in quantum science, memory storage, and various industries,” Vaidya added.