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Publications

Continuous Néel-VBS quantum phase transition in non-local one-dimensional systems with SO(3) symmetry

Cornell Affiliated Author(s)
Author
C.-M. Jian
Y. Xu
X.-C. Wu
C. Xu
Abstract

One dimensional (1d) interacting systems with local Hamiltonians can be studied with various well-developed analytical methods. Recently novel 1d physics was found numerically in systems with either spatially nonlocal interactions, or at the 1d boundary of 2d quantum critical points, and the critical fluctuation in the bulk also yields effective nonlocal interactions at the boundary. This work studies the edge states at the 1d boundary of 2d strongly interacting symmetry protected topological (SPT) states, when the bulk is driven to a disorder-order phase transition.

Journal
SciPost Physics
Date Published
Funding Source
1920434
Group (Lab)
Chao-Ming Jian Group

Semiconductor-less vertical transistor with I ON/I OFF of 106

Cornell Affiliated Author(s)
Author
J.-H. Lee
D.H. Shin
H. Yang
N.B. Jeong
D.-H. Park
K. Watanabe
T. Taniguchi
Eun-Ah Kim
S.W. Lee
S.H. Jhang
B.H. Park
Y. Kuk
H.-J. Chung
Abstract

Semiconductors have long been perceived as a prerequisite for solid-state transistors. Although switching principles for nanometer-scale devices have emerged based on the deployment of two-dimensional (2D) van der Waals heterostructures, tunneling and ballistic currents through short channels are difficult to control, and semiconducting channel materials remain indispensable for practical switching. In this study, we report a semiconductor-less solid-state electronic device that exhibits an industry-applicable switching of the ballistic current.

Journal
Nature Communications
Date Published
Group (Lab)

Enhanced optical absorption in conformally grown MoS2layers on SiO2/Si substrates with SiO2nanopillars with a height of 50 nm

Cornell Affiliated Author(s)
Author
H. Choi
Eun-Ah Kim
S. Kwon
J. Kim
A.D. Nguyen
S.-Y. Lee
E. Ko
S. Baek
H.-H. Park
Y.C. Park
K.-J. Yee
S. Yoon
Y.S. Kim
D.-W. Kim
Abstract

The integration of transition metal dichalcogenide (TMDC) layers on nanostructures has attracted growing attention as a means to improve the physical properties of the ultrathin TMDC materials. In this work, the influence of SiO2nanopillars (NPs) with a height of 50 nm on the optical characteristics of MoS2layers is investigated. Using a metal organic chemical vapor deposition technique, a few layers of MoS2were conformally grown on the NP-patterned SiO2/Si substrates without notable strain.

Journal
Nanoscale Advances
Date Published
Group (Lab)

Piezomagnetic switching and complex phase equilibria in uranium dioxide

Cornell Affiliated Author(s)
Author
D.J. Antonio
J.T. Weiss
K.S. Shanks
J.P.C. Ruff
M. Jaime
A. Saul
T. Swinburne
M. Salamon
K. Shrestha
B. Lavina
D. Koury
Sol Gruner
D.A. Andersson
C.R. Stanek
T. Durakiewicz
J.L. Smith
Z. Islam
K. Gofryk
Abstract

Actinide materials exhibit strong spin–lattice coupling and electronic correlations, and are predicted to host new emerging ground states. One example is piezomagnetism and magneto-elastic memory effect in the antiferromagnetic Mott-Hubbard insulator uranium dioxide, though its microscopic nature is under debate. Here, we report X-ray diffraction studies of oriented uranium dioxide crystals under strong pulsed magnetic fields. In the antiferromagnetic state a [888] Bragg diffraction peak follows the bulk magnetostriction that expands under magnetic fields.

Journal
Communications Materials
Date Published
Group (Lab)
Sol M. Gruner Group

High-pressure small-angle X-ray scattering cell for biological solutions and soft materials

Cornell Affiliated Author(s)
Author
D.K. Rai
R.E. Gillilan
Q. Huang
R. Miller
E. Ting
A. Lazarev
M.W. Tate
Sol Gruner
Abstract

Pressure is a fundamental thermodynamic parameter controlling the behavior of biological macromolecules. Pressure affects protein denaturation, kinetic parameters of enzymes, ligand binding, membrane permeability, ion transduction, expression of genetic information, viral infectivity, protein association and aggregation, and chemical processes. In many cases pressure alters the molecular shape. Small-angle X-ray scattering (SAXS) is a primary method to determine the shape and size of macromolecules.

Journal
Journal of Applied Crystallography
Date Published
Funding Source
NNCI-1542081
1-P30-GM124166-01A1
DMR-1829070
Research Area
Group (Lab)
Sol M. Gruner Group

Scale-invariant magnetic anisotropy in RuCl3 at high magnetic fields

Cornell Affiliated Author(s)
Author
K. Modic
Ross McDonald
J. Ruff
Maja Bachmann
You Lai
Johanna Palmstrom
David Graf
Mun Chan
Fedor Balakirev
Jon Betts
G.S. Boebinger
Marcus Schmidt
Michael Lawler
D. Sokolov
Philip Moll
B. Ramshaw
Arkady Shekhter
Abstract

In RuCl3, inelastic neutron scattering and Raman spectroscopy reveal a continuum of non-spin-wave excitations that persists to high temperature, suggesting the presence of a spin liquid state on a honeycomb lattice. In the context of the Kitaev model, finite magnetic fields introduce interactions between the elementary excitations, and thus the effects of high magnetic fields that are comparable to the spin-exchange energy scale must be explored.

Journal
Nature Physics
Date Published
Funding Source
DMR-1157490
DMR-1644779
1157490
1332208
Group (Lab)
Brad Ramshaw Group
Michael Lawler Group

Thermodynamic evidence for a two-component superconducting order parameter in Sr2RuO4

Cornell Affiliated Author(s)
Author
Sayak Ghosh
Arkady Shekhter
F. Jerzembeck
N. Kikugawa
Dmitry Sokolov
Manuel Brando
A. Mackenzie
Clifford Hicks
B. Ramshaw
Abstract

Sr2RuO4 has stood as the leading candidate for a spin-triplet superconductor for 26 years1. However, recent NMR experiments have cast doubt on this candidacy2,3 and it is difficult to find a theory of superconductivity that is consistent with all experiments. The order parameter symmetry for this material therefore remains an open question. Symmetry-based experiments are needed that can rule out broad classes of possible superconducting order parameters.

Journal
Nature Physics
Date Published
Group (Lab)
Brad Ramshaw Group

Topological orders competing for the Dirac surface state in FeSeTe surfaces

Cornell Affiliated Author(s)
Author
X. Wu
S.B. Chung
C. Liu
Eun-Ah Kim
Abstract

FeSeTe has recently emerged as a leading candidate material for the two-dimensional topological superconductivity (TSC). Two reasons for the excitement are the high Tc of the system and the fact that the Majorana zero modes (MZMs) inside the vortex cores live on the exposed surface rather than at the interface of a heterostructure as in the proximitized topological insulators. However, the recent scanning tunneling spectroscopy data have shown that, contrary to the theoretical expectation, the MZM does not exist inside every vortex core.

Journal
Physical Review Research
Date Published
Group (Lab)

Analysis of magnetic vortex dissipation in Sn-segregated boundaries in Nb3Sn superconducting RF cavities

Author
J. Carlson
A. Pack
M.K. Transtrum
J. Lee
D.N. Seidman
D.B. Liarte
N.S. Sitaraman
A. Senanian
M.M. Kelley
J.P. Sethna
Tomas Arias
S. Posen
Abstract

We study mechanisms of vortex nucleation in Nb3Sn superconducting RF (SRF) cavities using a combination of experimental, theoretical, and computational methods. Scanning transmission electron microscopy imaging and energy dispersive spectroscopy of some Nb3Sn cavities show Sn segregation at grain boundaries in Nb3Sn with Sn concentration as high as ∼35 at. % and widths ∼3 nm in chemical composition. Using ab initio calculations, we estimate the effect excess tin has on the local superconducting properties of the material.

Journal
Physical Review B
Date Published
Funding Source
NSF DMR-1720139
DE-AC02-07CH11359
DMR-0420532
N00014-0400798
N00014-0610539
N00014-0910781
N00014-1712870
ECCS-1542205
NSF ECCS-1542205
OIA-1549132
DMR-1121262
Group (Lab)
James Sethna Group
Tomas Arias Group

Publisher Correction: Magnetic field detection limits for ultraclean graphene Hall sensors (Nature Communications, (2020), 11, 1, (4163), 10.1038/s41467-020-18007-5)

Cornell Affiliated Author(s)
Author
B.T. Schaefer
L. Wang
A. Jarjour
K. Watanabe
T. Taniguchi
P.L. McEuen
K.C. Nowack
Abstract

The original version of this Article contained an error in Fig. 4f, in which the units on the vertical axis should be “(nT Hz−1/2)”, as opposed to “(nV Hz−1/2)”. This has been corrected in both the PDF and HTML versions of the Article. © 2021, The Author(s).

Journal
Nature Communications
Date Published
Group (Lab)
Katja Nowack Group