From EF6.1, we have a way of specifying a clustered index on a property
public class Person
{
[Index(IsClustered = true, IsUnique = true)]
public long U
From the current EF Core documentation - Indexes section:
Data Annotations
Indexes can not be created using data annotations.
But for sure you can specify that via Fluent API (note the extension methods having ForSqlServer prefix which seem to denote SqlServer specific features):
modelBuilder.Entity()
.HasIndex(e => e.UserName)
.IsUnique()
.ForSqlServerIsClustered();