Publications

@article{nokey,

title = {Probing the topological band structure of diffusive multiterminal Josephson junction devices with conductance measurements},

author = {Venkat Chandrasekhar},

url = {https://arxiv.org/abs/2209.04743

https://aip.scitation.org/doi/full/10.1063/5.0125708},

year  = {2022},

date = {2022-09-10},

urldate = {2022-09-10},

journal = {Applied Physics Letters},

volume = {121},

pages = {222601},

abstract = {The energy of an Andreev bound state in a clean normal metal in contact with two superconductors disperses with the difference Δϕ in the superconducting phase between the superconductors in much the same way as the energies of electrons in a one-dimensional crystal disperse with the crystal momentum k of the electrons. A normal metal with n superconductors maps on to a n−1 dimensional crystal, each dimension corresponding to the phase difference ϕi between a specific pair of superconductors. The resulting band structure as a function of the phase differences {Δϕi} has been proposed to have a topological nature, with gapped regions characterized by different Chern numbers separated by regions where the gap in the quasiparticle spectrum closes. A similar complex evolution of the quasiparticle spectrum with {Δϕi} has also been predicted for diffusive normal metals in contact with multiple superconductors. Here we show that the variation of the density of states at the Fermi energy of such a system can be directly probed by relatively simple conductance measurements, allowing rapid characterization of the energy spectrum.},

keywords = {Andreev reflection, Mesoscopic quantum transport, phase coherence, Proximity effect, Superconductivity},

pubstate = {published},

tppubtype = {article}

}

@article{Bal2018,

title = {Low temperature magnetoresistance of (111) (La0.3Sr0.7)(Al0.65Ta0.35)/SrTiO3},

author = {V. V. Bal and Z. Huang and K. Han and Ariando and T. Venkatesan and V. Chandrasekhar},

url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.99.035408},

doi = {https://doi.org/10.1103/PhysRevB.99.035408},

year  = {2019},

date = {2019-01-03},

journal = {Physical Review B},

volume = {99},

pages = {035408},

abstract = {The two-dimensional conducting interfaces in SrTiO3-based systems are known to show a variety of coexisting and competing phenomena in a complex phase space. Magnetoresistance measurements, which are typically used to extract information about the various interactions in these systems, must be interpreted with care, since multiple interactions can contribute to the resistivity in a given range of magnetic field and temperature. Here we review all the phenomena that can contribute to transport in SrTiO3-based conducting interfaces at low temperatures. We apply this understanding to the perpendicular magnetoresistance data of the high-mobility system of (111) oriented (La0.3Sr0.7)(Al0.65Ta0.35)O3/STO heterostructures, and find an excess negative magnetoresistance contribution which cannot be explained by weak localization alone. We argue that contributions from magnetic scattering as well as electron-electron interactions, combined with weak localization/antilocalization, can provide a possible explanation for the observed magnetoresistance.},

keywords = {epitaxial, magnetic impurity, Magnetism, perovskite, phase coherence, spin glass, Superconductivity},

pubstate = {published},

tppubtype = {article}

}

@article{zhang_signatures_2006,

title = {Signatures of phase coherence in the low-temperature transport properties of multiwall carbon nanotubes},

author = { Zhengfan Zhang and Venkat Chandrasekhar},

url = {http://link.aps.org/doi/10.1103/PhysRevB.73.075421},

doi = {10.1103/PhysRevB.73.075421},

issn = {1098-0121, 1550-235X},

year  = {2006},

date = {2006-02-01},

urldate = {2016-12-29},

journal = {Physical Review B},

volume = {73},

number = {7},

keywords = {Mesoscopic quantum transport, Nanotube, phase coherence},

pubstate = {published},

tppubtype = {article}

}

@article{Jiang2005b,

title = {Quantitative measurements of the thermal resistance of Andreev interferometers},

author = {Zhigang Jiang and Venkat Chandrasekhar},

url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.72.020502},

doi = {https://doi.org/10.1103/PhysRevB.72.020502},

year  = {2005},

date = {2005-07-08},

journal = {Physical Review B},

volume = {72},

pages = {020502(R)},

abstract = {Using a local thermometry technique, we have been able to quantitatively measure the thermal resistance RT of diffusive Andreev interferometers. We find that RT is strongly enhanced from its normal-state value at low temperatures, and behaves nonlinearly as a function of the thermal current through the sample. We also find that RT oscillates as a function of magnetic flux with a fundamental period corresponding to one flux quantum Φ0=h∕2e, demonstrating the phase-coherent nature of thermal transport in these devices. The magnitude of RT is larger than predicted by recent numerical simulations.},

keywords = {Andreev reflection, Mesoscopic quantum transport, phase coherence, Proximity effect, Superconductivity},

pubstate = {published},

tppubtype = {article}

}

@article{jiang_thermal_2005,

title = {Thermal Conductance of Andreev Interferometers},

author = { Z. Jiang and V. Chandrasekhar},

url = {http://link.aps.org/doi/10.1103/PhysRevLett.94.147002},

doi = {10.1103/PhysRevLett.94.147002},

issn = {0031-9007, 1079-7114},

year  = {2005},

date = {2005-04-01},

urldate = {2016-12-29},

journal = {Physical Review Letters},

volume = {94},

number = {14},

keywords = {Andreev reflection, phase coherence, Proximity effect, Superconductivity, thermal transport},

pubstate = {published},

tppubtype = {article}

}

@article{jiang_symmetry_2005,

title = {The symmetry of phase-coherent thermopower oscillations in Andreev interferometers},

author = { Zhi-Gang Jiang and Venkat Chandrasekhar},

url = {http://www.airitilibrary.com/Publication/alDetailedMesh?docid=05779073-200506-201210080013-201210080013-693-701},

year  = {2005},

date = {2005-01-01},

urldate = {2016-12-28},

journal = {Chinese Journal of Physics},

volume = {43},

number = {3S},

pages = {693--701},

keywords = {Andreev reflection, phase coherence, Proximity effect, Superconductivity, thermal transport},

pubstate = {published},

tppubtype = {article}

}

@article{zhang_conduction_2004,

title = {Conduction in carbon nanotubes through metastable resonant states},

author = { Z Zhang and D. A Dikin and R. S Ruoff and V Chandrasekhar},

url = {http://stacks.iop.org/0295-5075/68/i=5/a=713?key=crossref.40daace9248237a3af208d6afdfb1034},

doi = {10.1209/epl/i2004-10266-6},

issn = {0295-5075, 1286-4854},

year  = {2004},

date = {2004-01-01},

urldate = {2016-12-28},

journal = {Europhysics Letters (EPL)},

volume = {68},

number = {5},

pages = {713--719},

keywords = {Mesoscopic quantum transport, Nanotube, phase coherence},

pubstate = {published},

tppubtype = {article}

}

@article{dikin_quantitative_2002,

title = {Quantitative measurements of the thermopower of Andreev interferometers},

author = { D. A. Dikin and S. Jung and V. Chandrasekhar},

url = {http://iopscience.iop.org/article/10.1209/epl/i2002-00499-9/meta},

doi = {10.1209/epl/i2002-00499-9},

issn = {0295-5075},

year  = {2002},

date = {2002-01-01},

urldate = {2016-12-28},

journal = {EPL},

volume = {57},

number = {4},

pages = {564},

keywords = {Andreev reflection, phase coherence, Proximity effect, thermal transport},

pubstate = {published},

tppubtype = {article}

}