Publications and Preprints
16.Diagnosing the origin of quantum oscillation beating in graphene
Magnetic quantum oscillations are usually periodic in inverse magnetic field, and their amplitude can beat when two nearby frequencies interfere. In graphene-based hexagonal systems such beating can arise from strain-induced pseudomagnetic fields, unequal valley populations, valley-dependent energy shifts, spin-orbit-coupling-induced band splitting, or Kekulé distortions. We show that the carrier density and magnetic field dependence of the beating nodes distinguishes these mechanisms: starting from Onsager's quantization relation, we derive scaling relations for the critical carrier density as a function of critical magnetic field, finding quadratic scaling for a pseudomagnetic field and linear scaling for a density-independent valley imbalance.
15.Planar Hall effect in single and bilayer Rashba systems
The planar Hall effect (PHE) is an anisotropic magnetotransport response generated by coplanar electric and magnetic fields, and its origin in two-dimensional Rashba systems has remained unclear. We identify two distinct mechanisms in single- and bilayer Rashba electron gases. Zeeman coupling to an in-plane field distorts the Rashba-split dispersion and generates anisotropic carrier velocities, producing a PHE even without band geometric corrections. In asymmetric bilayers, interlayer delocalization generates finite planar Berry curvature and orbital magnetic moment, opening a separate geometric channel absent in a single layer. Symmetry analysis shows the leading response is quadratic in field with π-periodic angular dependence; the Zeeman channel dominates numerically, while the geometric channel is a smaller signature unique to asymmetric bilayers.
14.Intrinsic Magnetoelectric Hall Effect from Layer-Orbital Quantum Geometry
Intrinsic Hall effects, such as the anomalous Hall effect, originate from the orbital quantum geometry of Bloch states. However, in layered materials, the combined action of out-of-plane electric and magnetic fields couples to layer polarization and orbital moment, generating a mixed layer-orbital quantum geometry in field-dressed Bloch states. We show that this geometry produces an intrinsic magnetoelectric Hall effect that is bilinear in the electric and magnetic fields. The response is scattering-time independent and can arise in nonmagnetic systems without spin-orbit coupling. As a representative realization, we demonstrate the effect in rhombohedral pentalayer graphene, where the conductivity reaches values of order 0.05 e²/h.
13.Valleytronics in 2D Materials Roadmap
Valleytronics exploits non-equivalent energy extrema in the electronic band structure of crystalline solids, the valley degree of freedom, to encode, manipulate, and read out information. This Roadmap brings together perspectives from leading experts to chart key opportunities and challenges at the forefront of 2D material valleytronics, from valley exciton physics and valley Hall effects to lightwave valleytronics and spin-valley qubits.
12.Nonlinear Landau fan diagram and aperiodic magnetic oscillations in three-dimensional systems
Quantum oscillations offer a powerful probe for the geometry and topology of the Fermi surface in metals. We extend the generalized Onsager relation to three-dimensional systems, deriving the B-dependent oscillation frequency and a generalized Lifshitz–Kosevich equation, and elucidate these effects in a 3D spin-orbit coupled system.
11.Disorder-driven Weyl-Kondo Semimetal Phase in WTe2
We report disorder-driven anisotropic Kondo screening and a spontaneous Hall effect in bulk WTe₂, a nonmagnetic type-II Weyl semimetal, with a large second-harmonic Hall signal exhibiting quadratic current scaling. This establishes disordered WTe₂ as a platform hosting Weyl-Kondo fermions.
10.Quantum transport spectroscopy of pseudomagnetic field in graphene Editors' Suggestion & PRL Cover
High-mobility graphene exhibits distinct beating patterns in Shubnikov–de Haas oscillations arising from valley-resolved Landau quantization under different effective magnetic fields, enabling extraction of strain-induced pseudomagnetic fields as small as a few millitesla.
9.Deterministic Switching in Altermagnets via Asymmetric Sublattice Spin Current
We demonstrate a deterministic switching mechanism in collinear altermagnets driven by asymmetric sublattice spin currents, enabling magnetic-field-free, deterministic 180° Néel vector reversal on picosecond timescales, even in centrosymmetric, weakly spin-orbit-coupled systems.
8.Symmetry-driven Intrinsic Nonlinear Pure Spin Hall Effect
We introduce the intrinsic nonlinear pure spin Hall effect (NPSHE), where linear and second-order charge Hall currents vanish. A symmetry analysis identifies 39 magnetic point groups supporting NPSHE, with first-principles calculations showing a significant effect in the Kramers-Weyl metal RhGe even at room temperature.
7.Odd-parity longitudinal magnetoconductivity in time-reversal symmetry broken materials
In time-reversal symmetric (TRS) materials, Onsager reciprocity forbids longitudinal magnetoconductivity odd in the magnetic field, leaving only even-B responses. We show that intrinsic TRS breaking in magnetic systems produces a leading B-linear longitudinal response, the odd-parity magnetoconductivity (OMC). We identify its band-geometric origin, establish the symmetry conditions under which it survives, and demonstrate that a finite OMC serves as a direct transport signature of intrinsic TRS breaking, including in systems where crystalline symmetries forbid the anomalous Hall effect.
6.Light-induced Nonlinear Resonant Spin Magnetization
We demonstrate light-induced nonlinear spin magnetization (LNSM), dominant in centrosymmetric materials, and predict significant helicity-dependent LNSM in the antiferromagnet CuMnAs under circularly polarized light, opening routes to opto-spintronic devices.
5.Observation of the Magnetic Field Induced Fermi Surface Expansion in Aperiodic Quantum Oscillations
We present evidence of magnetic-field-induced Fermi surface expansion, captured via aperiodic quantum oscillations in resistivity at the LaVO₃/KTaO₃ and EuO/KTaO₃ interfaces, which are small-Fermi-surface systems where magnetic-susceptibility corrections become substantial.
4.Giant gate-controlled room temperature odd-parity magnetoresistance in magnetized bilayer graphene
We report giant room-temperature odd-parity magnetoresistance in a bilayer graphene/Cr₂Ge₂Te₆ heterostructure, tunable via electrostatic gating, arising from the coupling of out-of-plane Berry curvature and orbital magnetic moment to the applied field in a TRS-broken system.
3.Planar Hall Effect in Quasi-Two-Dimensional Materials Editors' Suggestion
We demonstrate a unique 2D planar Hall effect (2DPHE) originating from hidden planar components of Berry curvature and orbital magnetic moment in quasi-2D materials, and show in gated bilayer graphene that 2DPHE is sensitive to Lifshitz transitions.
2.Chiral anomalies in 3D spin-orbit coupled metals: electrical, thermal, and gravitational anomaly
We demonstrate electrical, thermal, and gravitational quantum chiral anomalies in 3D spin-orbit coupled systems, involving chiral charge transfer across two Fermi surfaces linked to a single Weyl-like point, with implications for the spin Nernst effect.
1.Nonlinear magnetoconductivity in Weyl and multi-Weyl semimetals in quantizing magnetic field
We investigate the second-order nonlinear magnetoconductivity of tilted type-I Weyl and multi-Weyl semimetals, predicting a finite longitudinal nonlinear magnetoconductivity in inversion-symmetry-broken, tilted Weyl semimetals that can determine tilt orientation experimentally.
*Equal contribution.
Outreach Activities
- Presented a talk at Research Scholar Day, Department of Physics 2026, IIT Kanpur
- Presented a poster at the 847. WE-Heraeus-Seminar, Physikzentrum, Germany
- Presented a talk at the Institute Research Symposium 2025, IIT Kanpur, India
- Presented a poster, "Planar Hall Effect in Quasi-Two-Dimensional Materials," at Graphene 2025, San Sebastián, Spain
- Presented a poster, "Planar Hall Effect in Quasi-Two-Dimensional Materials," at the PMRF Symposium 2025, IIT Hyderabad
- Presented a poster, "Planar Hall Effect in Quasi-Two-Dimensional Materials," at QMAT 2025, IIT Guwahati
- Delivered a talk at the in-house symposium, Condensed Matter Theory Division, IIT Kanpur
- Presented a poster, "Nonlinear magnetoconductivity in Weyl semimetals in quantizing magnetic field," at Emergent Phenomena in van der Waals Heterostructures, TIFR Mumbai
- Presented a poster and volunteered on the local organizing committee for QMAT 2022, IIT Kanpur