ABSTRACT
Over the past decades, it has been widely observed that many quantum and topological materials demonstrate a strong magnetoresistance (MR) at low temperature. In extreme cases, the resistivity at 4 K and under a finite field of ~10T can exceed room temperature resistivity by several times with an anomaly in its temperature dependence. Many mechanisms have been proposed in the literature, ranging from carrier compensation, open orbit, hot spots, to other exotic but less universal ones. Because many of the systems are often low-carrier-density metals, the physics are expected to be quasi-classical. We first approach this topic based on charge and spin density waves (CDW/SDW) materials with a focus on their linear MR at the low field limit [1]. We were able to connect the specific linear functional form to Pippard’s sharp-corner model and further explain the MR anomaly’s sensitivity to disorder, where the nature of corners of ~10-4 Å-1 curvature can be traced to the unique electronic structure based on a superposition of two incommensurate reciprocal space lattices [2]. We further construct an experimental narrative to universally address systems with MR anomaly, of both linear and parabolic MR behavior. Here we focus on highly conductive elemental metals Cr, Mo, and W, with either an open orbit or charge compensation always satisfied [3]. Without fully circling the Landau levels, the sharp corner mechanism of the MR anomaly places the phenomena in between SdH quantum oscillations and classical transport with Kohler’s scaling satisfied [3]. Our proposed sharp corner origin of MR anomaly is affine to both Abrikosov’s quantum magnetoresistance and carrier localization in Integer Quantum Hall systems. The quantum nature necessarily explains this MR’s anomaly’s sensitivity to disorder.
[1] Y. Feng et al., PNAS 116, 11201 (2019).
[2] Y. Feng et al., PNAS 121, e2315787121 (2024).
[3] Y. Feng et al., Matter 8, 102105 (2025).
BIOGRAPHY
Prof. Feng is a Chinese-American physicist specializing in condensed matter physics, magnetism, and correlated electron systems. He earned his B.S. in Physics from Fudan University in China in 1996, followed by an M.A. in Physics from The City College of New York in 1999, an M.S. in Physics from the University of Washington in 2002, and a Ph.D. in Physics from the University of Washington in 2003. After his doctorate, Feng held research positions, including as a physicist at Argonne National Laboratory from 2007 to 2016 and an affiliation with the California Institute of Technology since 2015. Since February 2017, he has served as an Associate Professor at the Okinawa Institute of Science and Technology (OIST) in Japan, where he leads the Electronic and Quantum Magnetism Unit. His work has garnered over 1,400 citations, with notable contributions to topics like quantum interference in superposed lattices.
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