Nonconservation of the Valley Density and Its Implications for the Observation of the Valley Hall Effect
We show that the conservation of the valley density in multivalley insulators is broken in an unexpected way by the electric field that drives the valley Hall effect. This implies that time-reversal-invariant fully gapped insulators, in which no bulk or edge state crosses the Fermi level, can support a valley Hall current in the bulk and yet show no valley density accumulation at the edges. Thus, the valley Hall effect cannot be observed in such systems. If the system is not fully gapped then valley density accumulation at the edges is possible. The accumulation has no contribution from undergap states and can be expressed as a Fermi surface average, for which we derive an explicit formula. We demonstrate the theory by calculating the valley density accumulations in an archetypical valley-Hall insulator: a gapped graphene nanoribbon. Surprisingly, we discover that a net valley density polarization is dynamically generated for certain edge terminations.
| Medienart: |
E-Artikel |
|---|
| Erscheinungsjahr: |
2024 |
|---|---|
| Erschienen: |
2024 |
| Enthalten in: |
Zur Gesamtaufnahme - volume:132 |
|---|---|
| Enthalten in: |
Physical review letters - 132(2024), 10 vom: 08. März, Seite 106301 |
| Sprache: |
Englisch |
|---|
| Beteiligte Personen: |
Kazantsev, Alexander [VerfasserIn] |
|---|
| Links: |
|---|
| Themen: |
|---|
| Anmerkungen: |
Date Revised 22.03.2024 published: Print Citation Status PubMed-not-MEDLINE |
|---|
| doi: |
10.1103/PhysRevLett.132.106301 |
|---|
| funding: |
|
|---|---|
| Förderinstitution / Projekttitel: |
|
| PPN (Katalog-ID): |
NLM370078691 |
|---|
| LEADER | 01000naa a22002652 4500 | ||
|---|---|---|---|
| 001 | NLM370078691 | ||
| 003 | DE-627 | ||
| 005 | 20240324000016.0 | ||
| 007 | cr uuu---uuuuu | ||
| 008 | 240324s2024 xx |||||o 00| ||eng c | ||
| 024 | 7 | |a 10.1103/PhysRevLett.132.106301 |2 doi | |
| 028 | 5 | 2 | |a pubmed24n1343.xml |
| 035 | |a (DE-627)NLM370078691 | ||
| 035 | |a (NLM)38518303 | ||
| 040 | |a DE-627 |b ger |c DE-627 |e rakwb | ||
| 041 | |a eng | ||
| 100 | 1 | |a Kazantsev, Alexander |e verfasserin |4 aut | |
| 245 | 1 | 0 | |a Nonconservation of the Valley Density and Its Implications for the Observation of the Valley Hall Effect |
| 264 | 1 | |c 2024 | |
| 336 | |a Text |b txt |2 rdacontent | ||
| 337 | |a ƒaComputermedien |b c |2 rdamedia | ||
| 338 | |a ƒa Online-Ressource |b cr |2 rdacarrier | ||
| 500 | |a Date Revised 22.03.2024 | ||
| 500 | |a published: Print | ||
| 500 | |a Citation Status PubMed-not-MEDLINE | ||
| 520 | |a We show that the conservation of the valley density in multivalley insulators is broken in an unexpected way by the electric field that drives the valley Hall effect. This implies that time-reversal-invariant fully gapped insulators, in which no bulk or edge state crosses the Fermi level, can support a valley Hall current in the bulk and yet show no valley density accumulation at the edges. Thus, the valley Hall effect cannot be observed in such systems. If the system is not fully gapped then valley density accumulation at the edges is possible. The accumulation has no contribution from undergap states and can be expressed as a Fermi surface average, for which we derive an explicit formula. We demonstrate the theory by calculating the valley density accumulations in an archetypical valley-Hall insulator: a gapped graphene nanoribbon. Surprisingly, we discover that a net valley density polarization is dynamically generated for certain edge terminations | ||
| 650 | 4 | |a Journal Article | |
| 700 | 1 | |a Mills, Amelia |e verfasserin |4 aut | |
| 700 | 1 | |a O'Neill, Eoin |e verfasserin |4 aut | |
| 700 | 1 | |a Sun, Hao |e verfasserin |4 aut | |
| 700 | 1 | |a Vignale, Giovanni |e verfasserin |4 aut | |
| 700 | 1 | |a Principi, Alessandro |e verfasserin |4 aut | |
| 773 | 0 | 8 | |i Enthalten in |t Physical review letters |d 1985 |g 132(2024), 10 vom: 08. März, Seite 106301 |w (DE-627)NLM099656183 |x 1079-7114 |7 nnns |
| 773 | 1 | 8 | |g volume:132 |g year:2024 |g number:10 |g day:08 |g month:03 |g pages:106301 |
| 856 | 4 | 0 | |u http://dx.doi.org/10.1103/PhysRevLett.132.106301 |3 Volltext |
| 912 | |a GBV_USEFLAG_A | ||
| 912 | |a GBV_NLM | ||
| 951 | |a AR | ||
| 952 | |d 132 |j 2024 |e 10 |b 08 |c 03 |h 106301 | ||