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Publications

Single-Molecule Optical-Trapping Techniques to Study Molecular Mechanisms of a Replisome

Cornell Affiliated Author(s)
Author
B. Sun
M.D. Wang
Abstract

The replisome is a multiprotein molecular machinery responsible for the replication of DNA. It is composed of several specialized proteins each with dedicated enzymatic activities, and in particular, helicase unwinds double-stranded DNA and DNA polymerase catalyzes the synthesis of DNA. Understanding how a replisome functions in the process of DNA replication requires methods to dissect the mechanisms of individual proteins and of multiproteins acting in concert.

Journal
Methods in Enzymology
Date Published
Research Area
Group (Lab)
Michelle Wang Group

Time-resolved terahertz studies of conductivity processes in novel electronic materials

Cornell Affiliated Author(s)
Author
J. Shan
S.L. Dexheimer
Abstract

Terahertz (THz) spectroscopy based on femtosecond laser techniques1-12 has emerged as a powerful probe of charge transport and carrier dynamics. The technique makes use of ultrashort pulses of propagating electromagnetic radiation to measure conductivity in the THz spectral regime.

Journal
Terahertz Spectroscopy: Principles and Applications
Date Published
Group (Lab)
Jie Shan Group

Dimensional crossover in a spin-imbalanced Fermi gas

Cornell Affiliated Author(s)
Author
S. Dutta
E.J. Mueller
Abstract

We model the one-dimensional (1D) to three-dimensional (3D) crossover in a cylindrically trapped Fermi gas with attractive interactions and spin imbalance. We calculate the mean-field phase diagram and study the relative stability of exotic superfluid phases as a function of interaction strength and temperature. For weak interactions and low density, we find 1D-like behavior, which repeats as a function of the chemical potential as new channels open. For strong interactions, mixing of single-particle levels gives 3D-like behavior at all densities.

Journal
Physical Review A
Date Published
Funding Source
1508300
PHY-1508300

Characterization of CdTe sensors with Schottky contacts coupled to charge-integrating pixel array detectors for X-ray science

Cornell Affiliated Author(s)
Author
J. Becker
M.W. Tate
K.S. Shanks
H.T. Philipp
J.T. Weiss
P. Purohit
Darol Chamberlain
J.P.C. Ruff
Sol Gruner
Abstract

Pixel Array Detectors (PADs) consist of an x-ray sensor layer bonded pixel-by-pixel to an underlying readout chip. This approach allows both the sensor and the custom pixel electronics to be tailored independently to best match the x-ray imaging requirements. Here we present characterizations of CdTe sensors hybridized with two different charge-integrating readout chips, the Keck PAD and the Mixed-Mode PAD (MM-PAD), both developed previously in our laboratory.

Journal
Journal of Instrumentation
Date Published
Funding Source
DMR-1332208
DE-FG02-1-0ER46693
DE-SC0016035
1332208
Group (Lab)
Sol M. Gruner Group

The novel metallic states of the cuprates: Topological Fermi liquids and strange metals

Cornell Affiliated Author(s)
Author
S. Sachdev
Debanjan Chowdhury
Abstract

We review ideas on the nature of the metallic states of the hole-doped cuprate high temperature superconductors, with an emphasis on the connections between the Luttinger theorem for the size of the Fermi surface, topological quantum field theories (TQFTs), and critical theories involving changes in the size of the Fermi surface.We begin with the derivation of the Luttinger theorem for a Fermi liquid, using momentum balance during a process of flux insertion in a lattice electronic model with toroidal boundary conditions.

Journal
Progress of Theoretical and Experimental Physics
Date Published
Funding Source
DMR-1360789
1360789
W911NF-14-1-0003
Group (Lab)
Debanjan Chowdhury Group

The response of small SQUID pickup loops to magnetic fields

Cornell Affiliated Author(s)
Author
John Kirtley
Lisa Paulius
Aaron Rosenberg
Johanna Palmstrom
Daniel Schiessl
Colin Jermain
Jonathan Gibbons
Connor Holland
Y.-K.-K. Fung
Martin Huber
Mark Ketchen
Daniel Ralph
Gerald Gibson
Kathryn Moler
Abstract

In the past, magnetic images acquired using scanning superconducting quantum interference device (SQUID) microscopy have been interpreted using simple models for the sensor point spread function. However, more complicated modeling is needed when the characteristic dimensions of the field sensitive areas in these sensors become comparable to the London penetration depth. In this paper we calculate the response of SQUIDs with deep sub-micron pickup loops to different sources of magnetic fields by solving coupled London's and Maxwell's equations using the full sensor geometry.

Journal
IOP Publishing
Date Published
Funding Source
DGE-114747
DMR-0957616
DMR-1406333
DMR-1120296
ECCS-1542081

Variation in superconducting transition temperature due to tetragonal domains in two-dimensionally doped SrTiO3

Cornell Affiliated Author(s)
Author
H. Noad
E.M. Spanton
K.C. Nowack
H. Inoue
M. Kim
T.A. Merz
C. Bell
Y. Hikita
R. Xu
W. Liu
A. Vailionis
H.Y. Hwang
K.A. Moler
Abstract

Strontium titanate is a low-temperature, non-Bardeen-Cooper-Schrieffer superconductor that superconducts to carrier concentrations lower than in any other system and exhibits avoided ferroelectricity at low temperatures. Neither the mechanism of superconductivity in strontium titanate nor the importance of the structure and dielectric properties for the superconductivity are well understood. We studied the effects of twin structure on superconductivity in a 5.5-nm-thick layer of niobium-doped SrTiO3 embedded in undoped SrTiO3.

Journal
Physical Review B
Date Published
Funding Source
DGE-114747
DE-AC02-06CH11357
DE-AC02-76SF00515
Group (Lab)
Katja Nowack Group

Two-dimensional spin liquids with Z 2 topological order in an array of quantum wires

Cornell Affiliated Author(s)
Author
Aavishkar Patel
Debanjan Chowdhury
Abstract

Insulating Z2 spin liquids are a phase of matter with bulk anyonic quasiparticle excitations and ground-state degeneracies on manifolds with nontrivial topology. We construct a time-reversal symmetric Z2 spin liquid in two spatial dimensions using an array of quantum wires. We identify the anyons as kinks in the appropriate Luttinger-liquid description, compute their mutual statistics, and construct local operators that transport these quasiparticles.

Journal
Physical Review B
Date Published
Funding Source
DMR-1360789
GBMF-4303
DMR-13001648
Group (Lab)
Debanjan Chowdhury Group

Commensurate 4a0-period charge density modulations throughout the Bi2Sr2CaCu2O8+xpseudogap regime

Cornell Affiliated Author(s)
Author
A. Mesaros
K. Fujita
S.D. Edkins
M.H. Hamidian
H. Eisaki
S.-I. Uchida
J.C.S. Davis
M.J. Lawler
Eun-Ah Kim
Abstract

Theories based upon strong real space (r-space) electron-electron interactions have long predicted that unidirectional charge density modulations (CDMs) with four-unit-cell (4a0) periodicity should occur in the hole-doped cuprate Mott insulator (MI). Experimentally, however, increasing the hole density p is reported to cause the conventionally defined wavevector QA of the CDM to evolve continuously as if driven primarily by momentum-space (k-space) effects. Here we introduce phase-resolved electronic structure visualization for determination of the cuprate CDM wavevector.

Journal
Proceedings of the National Academy of Sciences of the United States of America
Date Published
Group (Lab)
J.C. Seamus Davis Group
Michael Lawler Group

Low-damping sub-10-nm thin films of lutetium iron garnet grown by molecular-beam epitaxy

Cornell Affiliated Author(s)
Author
C. Jermain
H. Paik
Sriharsha Aradhya
Robert Buhrman
D. Schlom
D. Ralph
Abstract

We analyze the structural and magnetic characteristics of (111)-oriented lutetium iron garnet (Lu3Fe5O12) films grown by molecular-beam epitaxy, for films as thin as 2.8 nm. Thickness-dependent measurements of the in- and out-of-plane ferromagnetic resonance allow us to quantify the effects of two-magnon scattering, along with the surface anisotropy and the saturation magnetization.

Journal
AIP Publishing
Date Published
Funding Source
1120296
1406333