Embedded Files
Effect of Magnetic field on Graphene:
Effect of Magnetic field on Graphene:
Due to its very special band structure and topological properties of the monolayer, few-layer graphene had a lot of interest in the past decade. I am interested in the strong magnetic field limit. We have discovered that for 1/q quantum flux per unit cell there are 2q Dirac points in the non-interacting limit of monolayer Graphene. We also study Interacting cases to find the possible phases.
"Stability of Zero-energy Dirac touchings in the honeycomb Hofstadter problem", Ankur Das, Ribhu K. Kaul, and Ganpathy Murthy, PRB 101, 165416 (2020)
"Coexistence of Canted Antiferromagnetism and Bond-order in ν = 0 Graphene", Ankur Das, Ribhu K. Kaul, Ganpathy Murthy, PRL 128, 106803 (2022)
"Global phase diagram of charge neutral graphene in the quantum Hall regime for generic interactions", Suman Jyoti De, Ankur Das, Sumathi Rao, Ribhu K. Kaul, Ganpathy Murthy, Phys. Rev. B 107, 125422 (2023)
"Fractional Quantum Hall phases of graphene beyond ultra-short range intervalley-anisotropic interaction", Oleg Grigorev, Ankur Das, PRB 111, 035153 (2025) (PRB accepted)
"Half-quantized Hall Plateaus in the Confined Geometry of Graphene", Preeti Pandey, Sourav Manna, Kristiana N. Frei, Jerin Saji, Anne Denis, Alexander Savin, Kenji Watanabe, Takashi Taniguchi, Pertti J. Hakonen, Ankur Das, Manohar Kumar, arXiv:2410.03896
"Half-integer thermal conductance in the absence of Majorana mode", Ujjal Roy, Sourav Manna, Souvik Chakraborty, Kenji Watanabe, Takashi Taniguchi, Ankur Das, Moshe Goldstein, Yuval Gefen, Anindya Das, arXiv:2506.12526
Fractional Quantum Hall Effect, Edge Reconstruction, and Shot Noise:
Fractional Quantum Hall Effect, Edge Reconstruction, and Shot Noise:
The fraction Quantum Hall Effect in Graphene has many interesting results which are not well understood, specifically ν=2/3, 5/3, etc. I am interested in understanding the bulk states that minimize the energy in the composite fermion picture. I am also interested in shot noise and its use in determining the bulk state of complicated fillings. The topic of reconstruction in a quantum Hall system was long proposed by Chamon and Wen back in 1994 (PRB) for a simple ν=1 edge. Later many more proposals were made for other edges (both integer and fractional cases). I am interested in studying edge reconstruction in bosonization language to understand their stability and effect on different measurements.
"Shot noise does not always provide the quasiparticle charge," Sourav Biswas, Rajarshi Bhattacharyya, Hemanta Kumar Kundu, Ankur Das, Moty Heiblum, Vladimir Umansky, Moshe Goldstein, Yuval Gefen, Nature Physics 18, 1476–1481 (2022), 2022
"Dc Electrical Current Generated by Upstream Neutral Modes," Ankur Das, Sumathi Rao, Yuval Gefen, Ganpathy Murthy, PRB 105, 165154 (2022)
"Full Classification of Transport on an Equilibrated 5/2 Edge", Sourav Manna *, Ankur Das *, Moshe Goldstein, Yuval Gefen, PRL 132, 136502 (2024), (Editor's suggestion) (*equal contribution)
"Multiple mechanisms for emerging conductance plateaus in fractional quantum Hall states," Sourav Manna, Ankur Das, Yuval Gefen, Moshe Goldstein, PRL 134, 256503 (2025)
"Shot noise as a diagnostic in the ν=2/3 fractional quantum Hall edge zoo", Sourav Manna, Ankur Das, Yuval Gefen, Moshe Goldstein, Low Temp. Phys. 1 December 2024; 50 (12): 1113–1122
Experimentally Motivated Order of Length Scales Affect Shot Noise, Sourav Manna, Ankur Das, arXiv: 2307.08264
Signatures of Candidate States of ν=12/5 in Shot Noise, Goutham Vinjamuri, Ankur Das, arXiv: 2504.06226
Nexus triple point and its classification:
Nexus triple point and its classification:
It has been shown recently that there is a paradigm beyond Dirac and Weyl semi-metal and they cannot be categorized using the same methods (Nexus fermion). I am trying to work out a more general mathematical object that can classify these bands. One can also ask about the stability of these structures and the effect of including interactions.
"SU(3) Fermions in a Three-band Graphene-like Model", Ankur Das and Sumiran Pujari, PRB 100, 125152 (2019)
"Topological character of three-dimensional nexus triple point degeneracies", Ankur Das and Sumiran Pujari, PRB 102, 235148 (2020)
"Punctured-Chern topological invariants for semi-metallic bandstructures", Ankur Das, Eyal Cornfeld, and Sumiran Pujari, PRL 130, 186202 (2023)
Topological Semimetals (e.g. Weyl, Nodal Line Semimetals)
Topological Semimetals (e.g. Weyl, Nodal Line Semimetals)
I am recently interested in Weyl Semimetal and their non-trivial topological behavior in the presence of a magnetic field. We found that in the presence of a Magnetic field, the system might go into coexistence. We also found that we can solve the problem analytically for some specific models.
"Time-reversal-broken Weyl Semimetal in the Hofstadter Regime", Faruk Abdulla, Ankur Das, Sumathi Rao, Ganpathy Murthy, SciPost Phys. Core 5, 014 (2022)
"Topological nodal line semimetals with chiral symmetry", Faruk Abdulla, Ganpathy Murthy, Ankur Das, arXiv:2311.18667
"Stable nodal line semimetals in the chiral classes in three dimensions", Faruk Abdulla, Ganpathy Murthy, Ankur Das, arXiv: 2401.02966
Double Layer Systems:
Double Layer Systems:
Even though monolayer systems and 2-dimensional electron gas have been studied for a long time, a lot of interest in two-layered systems has recently encouraged many new questions and interests. These include but are not limited to double-layer graphene, double-layer electron gas, twisted bilayer graphene, etc. The questions involve both topology and symmetries of these systems.
"Layer Coherent Phase in Double Layer graphene at ν1 = ν2 = 0", Amartya Saha and Ankur Das, PRB 105, 035405 (2022)
Renormalization Group analysis and Emergent field theory:
Renormalization Group analysis and Emergent field theory:
I am interested in the Renormalization group and understanding RG flow for large emergent gauge theories. I work on the RG flows and the stable and unstable fixed points in the theory by evaluating Fynmann diagrams.
"Phase Transition in SU(N)xU(1) Gauge Theory with Many Fundamental Bosons", Ankur Das, PRB 97, 214429 (2018)
Working with me:
Working with me:
Working with me:
Working with me:
I am looking for a PhD student. Please contact me if you are interested in things I am working on. If you are an Integrated PhD student at IISER, Tirupati please contact me for further discussion. If you are not at this moment a student at IISER, Tirupati the next student hiring will be in December 2024, and you have to join through the regular hiring process. CSIR JRF fellows are preferable.
Please write to me directly for summer projects, semester-long projects, or year-long projects (MS thesis). This will be according to the institute's rules and mutual consent/interest.
I am interested in working with postdoctoral fellows (via NPDF or other external funding sources). If you want to work with me please email me directly and we can discuss writing for funds together.
Page updated
Google Sites
Report abuse