Unconventional Superconducting Quantum Criticality in Monolayer WTe2

Fuente: arXiv
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Hauptverfasser: Song, Tiancheng, Jia, Yanyu, Yu, Guo, Tang, Yue, Wang, Pengjie, Singha, Ratnadwip, Gui, Xin, Uzan, Ayelet J., Onyszczak, Michael, Watanabe, Kenji, Taniguchi, Takashi, Cava, Robert J., Schoop, Leslie M., Ong, N. P., Wu, Sanfeng
Format: Preprint
Veröffentlicht: 2023
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author Song, Tiancheng
Jia, Yanyu
Yu, Guo
Tang, Yue
Wang, Pengjie
Singha, Ratnadwip
Gui, Xin
Uzan, Ayelet J.
Onyszczak, Michael
Watanabe, Kenji
Taniguchi, Takashi
Cava, Robert J.
Schoop, Leslie M.
Ong, N. P.
Wu, Sanfeng
author_facet Song, Tiancheng
Jia, Yanyu
Yu, Guo
Tang, Yue
Wang, Pengjie
Singha, Ratnadwip
Gui, Xin
Uzan, Ayelet J.
Onyszczak, Michael
Watanabe, Kenji
Taniguchi, Takashi
Cava, Robert J.
Schoop, Leslie M.
Ong, N. P.
Wu, Sanfeng
contents The superconductor to insulator or metal transition in two dimensions (2D) provides a valuable platform for studying continuous quantum phase transitions (QPTs) and critical phenomena. Distinct theoretical models, including both fermionic and bosonic localization scenarios, have been developed, but many questions remain unsettled despite decades of research. Extending Nernst experiments down to millikelvin temperatures, we uncover anomalous quantum fluctuations and identify an unconventional superconducting quantum critical point (QCP) in a gate-tuned excitonic quantum spin Hall insulator (QSHI), the monolayer tungsten ditelluride (WTe2). The observed vortex Nernst effect reveals singular superconducting fluctuations in the resistive normal state induced by magnetic fields or temperature, even well above the transition. Near the doping-induced QCP, the Nernst signal driven by quantum fluctuations is exceptionally large in the millikelvin regime, with a coefficient of ~ 4,100 uV/KT at zero magnetic field, an indication of the proliferation of vortices. Surprisingly, the Nernst signal abruptly disappears when the doping falls below the critical value, in striking conflict with conventional expectations. This series of phenomena, which have no prior analogue, call for careful examinations of the mechanism of the QCP, including the possibility of a continuous QPT between two distinct ordered phases in the monolayer. Our experiments open a new avenue for studying unconventional QPTs and quantum critical matter.
format Preprint
id arxiv_https___arxiv_org_abs_2303_06540
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Unconventional Superconducting Quantum Criticality in Monolayer WTe2
Song, Tiancheng
Jia, Yanyu
Yu, Guo
Tang, Yue
Wang, Pengjie
Singha, Ratnadwip
Gui, Xin
Uzan, Ayelet J.
Onyszczak, Michael
Watanabe, Kenji
Taniguchi, Takashi
Cava, Robert J.
Schoop, Leslie M.
Ong, N. P.
Wu, Sanfeng
Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
Superconductivity
The superconductor to insulator or metal transition in two dimensions (2D) provides a valuable platform for studying continuous quantum phase transitions (QPTs) and critical phenomena. Distinct theoretical models, including both fermionic and bosonic localization scenarios, have been developed, but many questions remain unsettled despite decades of research. Extending Nernst experiments down to millikelvin temperatures, we uncover anomalous quantum fluctuations and identify an unconventional superconducting quantum critical point (QCP) in a gate-tuned excitonic quantum spin Hall insulator (QSHI), the monolayer tungsten ditelluride (WTe2). The observed vortex Nernst effect reveals singular superconducting fluctuations in the resistive normal state induced by magnetic fields or temperature, even well above the transition. Near the doping-induced QCP, the Nernst signal driven by quantum fluctuations is exceptionally large in the millikelvin regime, with a coefficient of ~ 4,100 uV/KT at zero magnetic field, an indication of the proliferation of vortices. Surprisingly, the Nernst signal abruptly disappears when the doping falls below the critical value, in striking conflict with conventional expectations. This series of phenomena, which have no prior analogue, call for careful examinations of the mechanism of the QCP, including the possibility of a continuous QPT between two distinct ordered phases in the monolayer. Our experiments open a new avenue for studying unconventional QPTs and quantum critical matter.
title Unconventional Superconducting Quantum Criticality in Monolayer WTe2
topic Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
Superconductivity
url https://arxiv.org/abs/2303.06540